This file contains abstract classes for deterministic and probabilistic PyTorch Lightning Modules

class darts.models.forecasting.pl_forecasting_module.PLDualCovariatesModule(input_chunk_length, output_chunk_length, output_chunk_shift=0, train_sample_shape=None, loss_fn=MSELoss(), torch_metrics=None, likelihood=None, optimizer_cls=<class 'torch.optim.adam.Adam'>, optimizer_kwargs=None, lr_scheduler_cls=None, lr_scheduler_kwargs=None, use_reversible_instance_norm=False)[source]

Bases: PLForecastingModule, ABC

PyTorch Lightning-based Forecasting Module.

This class is meant to be inherited to create a new PyTorch Lightning-based forecasting module. When subclassing this class, please make sure to add the following methods with the given signatures:

  • PLForecastingModule.__init__()

  • PLForecastingModule.forward()

  • PLForecastingModule._produce_train_output()

  • PLForecastingModule._get_batch_prediction()

In subclass MyModel’s __init__() function call super(MyModel, self).__init__(**kwargs) where kwargs are the parameters of PLForecastingModule.

Parameters
  • input_chunk_length (int) – Number of time steps in the past to take as a model input (per chunk). Applies to the target series, and past and/or future covariates (if the model supports it).

  • output_chunk_length (int) – Number of time steps predicted at once (per chunk) by the internal model. Also, the number of future values from future covariates to use as a model input (if the model supports future covariates). It is not the same as forecast horizon n used in predict(), which is the desired number of prediction points generated using either a one-shot- or autoregressive forecast. Setting n <= output_chunk_length prevents auto-regression. This is useful when the covariates don’t extend far enough into the future, or to prohibit the model from using future values of past and / or future covariates for prediction (depending on the model’s covariate support).

  • train_sample_shape (Optional[Tuple]) – Shape of the model’s input, used to instantiate model without calling fit_from_dataset and perform sanity check on new training/inference datasets used for re-training or prediction.

  • loss_fn (_Loss) – PyTorch loss function used for training. This parameter will be ignored for probabilistic models if the likelihood parameter is specified. Default: torch.nn.MSELoss().

  • torch_metrics (Union[Metric, MetricCollection, None]) – A torch metric or a MetricCollection used for evaluation. A full list of available metrics can be found at https://torchmetrics.readthedocs.io/en/latest/. Default: None.

  • likelihood (Optional[Likelihood]) – One of Darts’ Likelihood models to be used for probabilistic forecasts. Default: None.

  • optimizer_cls (Optimizer) – The PyTorch optimizer class to be used. Default: torch.optim.Adam.

  • optimizer_kwargs (Optional[Dict]) – Optionally, some keyword arguments for the PyTorch optimizer (e.g., {'lr': 1e-3} for specifying a learning rate). Otherwise the default values of the selected optimizer_cls will be used. Default: None.

  • lr_scheduler_cls (Optional[_LRScheduler]) – Optionally, the PyTorch learning rate scheduler class to be used. Specifying None corresponds to using a constant learning rate. Default: None.

  • lr_scheduler_kwargs (Optional[Dict]) – Optionally, some keyword arguments for the PyTorch learning rate scheduler. Default: None.

  • use_reversible_instance_norm (bool) – Whether to use reversible instance normalization RINorm against distribution shift as shown in [1]. It is only applied to the features of the target series and not the covariates.

References

1

T. Kim et al. “Reversible Instance Normalization for Accurate Time-Series Forecasting against Distribution Shift”, https://openreview.net/forum?id=cGDAkQo1C0p

Attributes

automatic_optimization

If set to False you are responsible for calling .backward(), .step(), .zero_grad().

current_epoch

The current epoch in the Trainer, or 0 if not attached.

example_input_array

The example input array is a specification of what the module can consume in the forward() method.

global_rank

The index of the current process across all nodes and devices.

global_step

Total training batches seen across all epochs.

hparams

The collection of hyperparameters saved with save_hyperparameters().

hparams_initial

The collection of hyperparameters saved with save_hyperparameters().

local_rank

The index of the current process within a single node.

logger

Reference to the logger object in the Trainer.

loggers

Reference to the list of loggers in the Trainer.

on_gpu

Returns True if this model is currently located on a GPU.

output_chunk_length

Number of time steps predicted at once by the model.

strict_loading

Determines how Lightning loads this model using .load_state_dict(..., strict=model.strict_loading).

device

dtype

epochs_trained

fabric

supports_probabilistic_prediction

trainer

Methods

add_module(name, module)

Add a child module to the current module.

all_gather(data[, group, sync_grads])

Gather tensors or collections of tensors from multiple processes.

apply(fn)

Apply fn recursively to every submodule (as returned by .children()) as well as self.

backward(loss, *args, **kwargs)

Called to perform backward on the loss returned in training_step().

bfloat16()

Casts all floating point parameters and buffers to bfloat16 datatype.

buffers([recurse])

Return an iterator over module buffers.

children()

Return an iterator over immediate children modules.

clip_gradients(optimizer[, ...])

Handles gradient clipping internally.

compile(*args, **kwargs)

Compile this Module's forward using torch.compile().

configure_callbacks()

Configure model-specific callbacks.

configure_gradient_clipping(optimizer[, ...])

Perform gradient clipping for the optimizer parameters.

configure_model()

Hook to create modules in a strategy and precision aware context.

configure_optimizers()

configures optimizers and learning rate schedulers for model optimization.

configure_sharded_model()

Deprecated.

configure_torch_metrics(torch_metrics)

process the torch_metrics parameter.

cpu()

See torch.nn.Module.cpu().

cuda([device])

Moves all model parameters and buffers to the GPU.

double()

See torch.nn.Module.double().

eval()

Set the module in evaluation mode.

extra_repr()

Set the extra representation of the module.

float()

See torch.nn.Module.float().

forward(*args, **kwargs)

Same as torch.nn.Module.forward().

freeze()

Freeze all params for inference.

get_buffer(target)

Return the buffer given by target if it exists, otherwise throw an error.

get_extra_state()

Return any extra state to include in the module's state_dict.

get_parameter(target)

Return the parameter given by target if it exists, otherwise throw an error.

get_submodule(target)

Return the submodule given by target if it exists, otherwise throw an error.

half()

See torch.nn.Module.half().

ipu([device])

Move all model parameters and buffers to the IPU.

load_from_checkpoint(checkpoint_path[, ...])

Primary way of loading a model from a checkpoint.

load_state_dict(state_dict[, strict, assign])

Copy parameters and buffers from state_dict into this module and its descendants.

log(name, value[, prog_bar, logger, ...])

Log a key, value pair.

log_dict(dictionary[, prog_bar, logger, ...])

Log a dictionary of values at once.

lr_scheduler_step(scheduler, metric)

Override this method to adjust the default way the Trainer calls each scheduler.

lr_schedulers()

Returns the learning rate scheduler(s) that are being used during training.

manual_backward(loss, *args, **kwargs)

Call this directly from your training_step() when doing optimizations manually.

modules()

Return an iterator over all modules in the network.

named_buffers([prefix, recurse, ...])

Return an iterator over module buffers, yielding both the name of the buffer as well as the buffer itself.

named_children()

Return an iterator over immediate children modules, yielding both the name of the module as well as the module itself.

named_modules([memo, prefix, remove_duplicate])

Return an iterator over all modules in the network, yielding both the name of the module as well as the module itself.

named_parameters([prefix, recurse, ...])

Return an iterator over module parameters, yielding both the name of the parameter as well as the parameter itself.

on_after_backward()

Called after loss.backward() and before optimizers are stepped.

on_after_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch after it is transferred to the device.

on_before_backward(loss)

Called before loss.backward().

on_before_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch before it is transferred to the device.

on_before_optimizer_step(optimizer)

Called before optimizer.step().

on_before_zero_grad(optimizer)

Called after training_step() and before optimizer.zero_grad().

on_fit_end()

Called at the very end of fit.

on_fit_start()

Called at the very beginning of fit.

on_load_checkpoint(checkpoint)

Called by Lightning to restore your model.

on_predict_batch_end(outputs, batch, batch_idx)

Called in the predict loop after the batch.

on_predict_batch_start(batch, batch_idx[, ...])

Called in the predict loop before anything happens for that batch.

on_predict_end()

Called at the end of predicting.

on_predict_epoch_end()

Called at the end of predicting.

on_predict_epoch_start()

Called at the beginning of predicting.

on_predict_model_eval()

Called when the predict loop starts.

on_predict_start()

Called at the beginning of predicting.

on_save_checkpoint(checkpoint)

Called by Lightning when saving a checkpoint to give you a chance to store anything else you might want to save.

on_test_batch_end(outputs, batch, batch_idx)

Called in the test loop after the batch.

on_test_batch_start(batch, batch_idx[, ...])

Called in the test loop before anything happens for that batch.

on_test_end()

Called at the end of testing.

on_test_epoch_end()

Called in the test loop at the very end of the epoch.

on_test_epoch_start()

Called in the test loop at the very beginning of the epoch.

on_test_model_eval()

Called when the test loop starts.

on_test_model_train()

Called when the test loop ends.

on_test_start()

Called at the beginning of testing.

on_train_batch_end(outputs, batch, batch_idx)

Called in the training loop after the batch.

on_train_batch_start(batch, batch_idx)

Called in the training loop before anything happens for that batch.

on_train_end()

Called at the end of training before logger experiment is closed.

on_train_epoch_end()

Called in the training loop at the very end of the epoch.

on_train_epoch_start()

Called in the training loop at the very beginning of the epoch.

on_train_start()

Called at the beginning of training after sanity check.

on_validation_batch_end(outputs, batch, ...)

Called in the validation loop after the batch.

on_validation_batch_start(batch, batch_idx)

Called in the validation loop before anything happens for that batch.

on_validation_end()

Called at the end of validation.

on_validation_epoch_end()

Called in the validation loop at the very end of the epoch.

on_validation_epoch_start()

Called in the validation loop at the very beginning of the epoch.

on_validation_model_eval()

Called when the validation loop starts.

on_validation_model_train()

Called when the validation loop ends.

on_validation_model_zero_grad()

Called by the training loop to release gradients before entering the validation loop.

on_validation_start()

Called at the beginning of validation.

optimizer_step(epoch, batch_idx, optimizer)

Override this method to adjust the default way the Trainer calls the optimizer.

optimizer_zero_grad(epoch, batch_idx, optimizer)

Override this method to change the default behaviour of optimizer.zero_grad().

optimizers([use_pl_optimizer])

Returns the optimizer(s) that are being used during training.

parameters([recurse])

Return an iterator over module parameters.

predict_dataloader()

An iterable or collection of iterables specifying prediction samples.

predict_step(batch, batch_idx[, dataloader_idx])

performs the prediction step

prepare_data()

Use this to download and prepare data.

print(*args, **kwargs)

Prints only from process 0.

register_backward_hook(hook)

Register a backward hook on the module.

register_buffer(name, tensor[, persistent])

Add a buffer to the module.

register_forward_hook(hook, *[, prepend, ...])

Register a forward hook on the module.

register_forward_pre_hook(hook, *[, ...])

Register a forward pre-hook on the module.

register_full_backward_hook(hook[, prepend])

Register a backward hook on the module.

register_full_backward_pre_hook(hook[, prepend])

Register a backward pre-hook on the module.

register_load_state_dict_post_hook(hook)

Register a post hook to be run after module's load_state_dict is called.

register_module(name, module)

Alias for add_module().

register_parameter(name, param)

Add a parameter to the module.

register_state_dict_pre_hook(hook)

Register a pre-hook for the load_state_dict() method.

requires_grad_([requires_grad])

Change if autograd should record operations on parameters in this module.

save_hyperparameters(*args[, ignore, frame, ...])

Save arguments to hparams attribute.

set_extra_state(state)

Set extra state contained in the loaded state_dict.

set_predict_parameters(n, num_samples, ...)

to be set from TorchForecastingModel before calling trainer.predict() and reset at self.on_predict_end()

setup(stage)

Called at the beginning of fit (train + validate), validate, test, or predict.

share_memory()

See torch.Tensor.share_memory_().

state_dict(*args[, destination, prefix, ...])

Return a dictionary containing references to the whole state of the module.

teardown(stage)

Called at the end of fit (train + validate), validate, test, or predict.

test_dataloader()

An iterable or collection of iterables specifying test samples.

test_step(*args, **kwargs)

Operates on a single batch of data from the test set.

to(*args, **kwargs)

See torch.nn.Module.to().

to_dtype(dtype)

Cast module precision (float32 by default) to another precision.

to_empty(*, device[, recurse])

Move the parameters and buffers to the specified device without copying storage.

to_onnx(file_path[, input_sample])

Saves the model in ONNX format.

to_torchscript([file_path, method, ...])

By default compiles the whole model to a ScriptModule.

toggle_optimizer(optimizer)

Makes sure only the gradients of the current optimizer's parameters are calculated in the training step to prevent dangling gradients in multiple-optimizer setup.

train([mode])

Set the module in training mode.

train_dataloader()

An iterable or collection of iterables specifying training samples.

training_step(train_batch, batch_idx)

performs the training step

transfer_batch_to_device(batch, device, ...)

Override this hook if your DataLoader returns tensors wrapped in a custom data structure.

type(dst_type)

See torch.nn.Module.type().

unfreeze()

Unfreeze all parameters for training.

untoggle_optimizer(optimizer)

Resets the state of required gradients that were toggled with toggle_optimizer().

val_dataloader()

An iterable or collection of iterables specifying validation samples.

validation_step(val_batch, batch_idx)

performs the validation step

xpu([device])

Move all model parameters and buffers to the XPU.

zero_grad([set_to_none])

Reset gradients of all model parameters.

__call__

set_mc_dropout

CHECKPOINT_HYPER_PARAMS_KEY = 'hyper_parameters'
CHECKPOINT_HYPER_PARAMS_NAME = 'hparams_name'
CHECKPOINT_HYPER_PARAMS_TYPE = 'hparams_type'
T_destination

alias of TypeVar(‘T_destination’, bound=Dict[str, Any])

add_module(name, module)

Add a child module to the current module.

The module can be accessed as an attribute using the given name.

Parameters
  • name (str) – name of the child module. The child module can be accessed from this module using the given name

  • module (Module) – child module to be added to the module.

Return type

None

all_gather(data, group=None, sync_grads=False)

Gather tensors or collections of tensors from multiple processes.

This method needs to be called on all processes and the tensors need to have the same shape across all processes, otherwise your program will stall forever.

Parameters
  • data (Union[Tensor, Dict, List, Tuple]) – int, float, tensor of shape (batch, …), or a (possibly nested) collection thereof.

  • group (Optional[Any]) – the process group to gather results from. Defaults to all processes (world)

  • sync_grads (bool) – flag that allows users to synchronize gradients for the all_gather operation

Return type

Union[Tensor, Dict, List, Tuple]

Returns

A tensor of shape (world_size, batch, …), or if the input was a collection the output will also be a collection with tensors of this shape.

apply(fn)

Apply fn recursively to every submodule (as returned by .children()) as well as self.

Typical use includes initializing the parameters of a model (see also nn-init-doc).

Parameters

fn (Module -> None) – function to be applied to each submodule

Returns

self

Return type

Module

Example:

>>> @torch.no_grad()
>>> def init_weights(m):
>>>     print(m)
>>>     if type(m) == nn.Linear:
>>>         m.weight.fill_(1.0)
>>>         print(m.weight)
>>> net = nn.Sequential(nn.Linear(2, 2), nn.Linear(2, 2))
>>> net.apply(init_weights)
Linear(in_features=2, out_features=2, bias=True)
Parameter containing:
tensor([[1., 1.],
        [1., 1.]], requires_grad=True)
Linear(in_features=2, out_features=2, bias=True)
Parameter containing:
tensor([[1., 1.],
        [1., 1.]], requires_grad=True)
Sequential(
  (0): Linear(in_features=2, out_features=2, bias=True)
  (1): Linear(in_features=2, out_features=2, bias=True)
)
property automatic_optimization: bool

If set to False you are responsible for calling .backward(), .step(), .zero_grad().

Return type

bool

backward(loss, *args, **kwargs)

Called to perform backward on the loss returned in training_step(). Override this hook with your own implementation if you need to.

Parameters

loss (Tensor) – The loss tensor returned by training_step(). If gradient accumulation is used, the loss here holds the normalized value (scaled by 1 / accumulation steps).

Example:

def backward(self, loss):
    loss.backward()
Return type

None

bfloat16()

Casts all floating point parameters and buffers to bfloat16 datatype.

Note

This method modifies the module in-place.

Returns

self

Return type

Module

buffers(recurse=True)

Return an iterator over module buffers.

Parameters

recurse (bool) – if True, then yields buffers of this module and all submodules. Otherwise, yields only buffers that are direct members of this module.

Yields

torch.Tensor – module buffer

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for buf in model.buffers():
>>>     print(type(buf), buf.size())
<class 'torch.Tensor'> (20L,)
<class 'torch.Tensor'> (20L, 1L, 5L, 5L)
Return type

Iterator[Tensor]

call_super_init: bool = False
children()

Return an iterator over immediate children modules.

Yields

Module – a child module

Return type

Iterator[Module]

clip_gradients(optimizer, gradient_clip_val=None, gradient_clip_algorithm=None)

Handles gradient clipping internally.

Note

  • Do not override this method. If you want to customize gradient clipping, consider using configure_gradient_clipping() method.

  • For manual optimization (self.automatic_optimization = False), if you want to use gradient clipping, consider calling self.clip_gradients(opt, gradient_clip_val=0.5, gradient_clip_algorithm="norm") manually in the training step.

Parameters
  • optimizer (Optimizer) – Current optimizer being used.

  • gradient_clip_val (Union[int, float, None]) – The value at which to clip gradients.

  • gradient_clip_algorithm (Optional[str]) – The gradient clipping algorithm to use. Pass gradient_clip_algorithm="value" to clip by value, and gradient_clip_algorithm="norm" to clip by norm.

Return type

None

compile(*args, **kwargs)

Compile this Module’s forward using torch.compile().

This Module’s __call__ method is compiled and all arguments are passed as-is to torch.compile().

See torch.compile() for details on the arguments for this function.

configure_callbacks()

Configure model-specific callbacks. When the model gets attached, e.g., when .fit() or .test() gets called, the list or a callback returned here will be merged with the list of callbacks passed to the Trainer’s callbacks argument. If a callback returned here has the same type as one or several callbacks already present in the Trainer’s callbacks list, it will take priority and replace them. In addition, Lightning will make sure ModelCheckpoint callbacks run last.

Return type

Union[Sequence[Callback], Callback]

Returns

A callback or a list of callbacks which will extend the list of callbacks in the Trainer.

Example:

def configure_callbacks(self):
    early_stop = EarlyStopping(monitor="val_acc", mode="max")
    checkpoint = ModelCheckpoint(monitor="val_loss")
    return [early_stop, checkpoint]
configure_gradient_clipping(optimizer, gradient_clip_val=None, gradient_clip_algorithm=None)

Perform gradient clipping for the optimizer parameters. Called before optimizer_step().

Parameters
  • optimizer (Optimizer) – Current optimizer being used.

  • gradient_clip_val (Union[int, float, None]) – The value at which to clip gradients. By default, value passed in Trainer will be available here.

  • gradient_clip_algorithm (Optional[str]) – The gradient clipping algorithm to use. By default, value passed in Trainer will be available here.

Example:

def configure_gradient_clipping(self, optimizer, gradient_clip_val, gradient_clip_algorithm):
    # Implement your own custom logic to clip gradients
    # You can call `self.clip_gradients` with your settings:
    self.clip_gradients(
        optimizer,
        gradient_clip_val=gradient_clip_val,
        gradient_clip_algorithm=gradient_clip_algorithm
    )
Return type

None

configure_model()

Hook to create modules in a strategy and precision aware context.

This is particularly useful for when using sharded strategies (FSDP and DeepSpeed), where we’d like to shard the model instantly to save memory and initialization time. For non-sharded strategies, you can choose to override this hook or to initialize your model under the init_module() context manager.

This hook is called during each of fit/val/test/predict stages in the same process, so ensure that implementation of this hook is idempotent, i.e., after the first time the hook is called, subsequent calls to it should be a no-op.

Return type

None

configure_optimizers()

configures optimizers and learning rate schedulers for model optimization.

configure_sharded_model()

Deprecated.

Use configure_model() instead.

Return type

None

static configure_torch_metrics(torch_metrics)

process the torch_metrics parameter.

Return type

MetricCollection

cpu()

See torch.nn.Module.cpu().

Return type

Self

cuda(device=None)

Moves all model parameters and buffers to the GPU. This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on GPU while being optimized.

Parameters

device (Union[int, device, None]) – If specified, all parameters will be copied to that device. If None, the current CUDA device index will be used.

Returns

self

Return type

Module

property current_epoch: int

The current epoch in the Trainer, or 0 if not attached.

Return type

int

property device: device
Return type

device

double()

See torch.nn.Module.double().

Return type

Self

property dtype: Union[str, dtype]
Return type

Union[str, dtype]

dump_patches: bool = False
property epochs_trained
eval()

Set the module in evaluation mode.

This has any effect only on certain modules. See documentations of particular modules for details of their behaviors in training/evaluation mode, if they are affected, e.g. Dropout, BatchNorm, etc.

This is equivalent with self.train(False).

See locally-disable-grad-doc for a comparison between .eval() and several similar mechanisms that may be confused with it.

Returns

self

Return type

Module

property example_input_array: Optional[Union[Tensor, Tuple, Dict]]

The example input array is a specification of what the module can consume in the forward() method. The return type is interpreted as follows:

  • Single tensor: It is assumed the model takes a single argument, i.e., model.forward(model.example_input_array)

  • Tuple: The input array should be interpreted as a sequence of positional arguments, i.e., model.forward(*model.example_input_array)

  • Dict: The input array represents named keyword arguments, i.e., model.forward(**model.example_input_array)

Return type

Union[Tensor, Tuple, Dict, None]

extra_repr()

Set the extra representation of the module.

To print customized extra information, you should re-implement this method in your own modules. Both single-line and multi-line strings are acceptable.

Return type

str

property fabric: Optional[Fabric]
Return type

Optional[Fabric]

float()

See torch.nn.Module.float().

Return type

Self

abstract forward(*args, **kwargs)

Same as torch.nn.Module.forward().

Parameters
  • *args – Whatever you decide to pass into the forward method.

  • **kwargs – Keyword arguments are also possible.

Return type

Any

Returns

Your model’s output

freeze()

Freeze all params for inference.

Example:

model = MyLightningModule(...)
model.freeze()
Return type

None

get_buffer(target)

Return the buffer given by target if it exists, otherwise throw an error.

See the docstring for get_submodule for a more detailed explanation of this method’s functionality as well as how to correctly specify target.

Parameters

target (str) – The fully-qualified string name of the buffer to look for. (See get_submodule for how to specify a fully-qualified string.)

Returns

The buffer referenced by target

Return type

torch.Tensor

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not a buffer

get_extra_state()

Return any extra state to include in the module’s state_dict.

Implement this and a corresponding set_extra_state() for your module if you need to store extra state. This function is called when building the module’s state_dict().

Note that extra state should be picklable to ensure working serialization of the state_dict. We only provide provide backwards compatibility guarantees for serializing Tensors; other objects may break backwards compatibility if their serialized pickled form changes.

Returns

Any extra state to store in the module’s state_dict

Return type

object

get_parameter(target)

Return the parameter given by target if it exists, otherwise throw an error.

See the docstring for get_submodule for a more detailed explanation of this method’s functionality as well as how to correctly specify target.

Parameters

target (str) – The fully-qualified string name of the Parameter to look for. (See get_submodule for how to specify a fully-qualified string.)

Returns

The Parameter referenced by target

Return type

torch.nn.Parameter

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not an nn.Parameter

get_submodule(target)

Return the submodule given by target if it exists, otherwise throw an error.

For example, let’s say you have an nn.Module A that looks like this:

A(
    (net_b): Module(
        (net_c): Module(
            (conv): Conv2d(16, 33, kernel_size=(3, 3), stride=(2, 2))
        )
        (linear): Linear(in_features=100, out_features=200, bias=True)
    )
)

(The diagram shows an nn.Module A. A has a nested submodule net_b, which itself has two submodules net_c and linear. net_c then has a submodule conv.)

To check whether or not we have the linear submodule, we would call get_submodule("net_b.linear"). To check whether we have the conv submodule, we would call get_submodule("net_b.net_c.conv").

The runtime of get_submodule is bounded by the degree of module nesting in target. A query against named_modules achieves the same result, but it is O(N) in the number of transitive modules. So, for a simple check to see if some submodule exists, get_submodule should always be used.

Parameters

target (str) – The fully-qualified string name of the submodule to look for. (See above example for how to specify a fully-qualified string.)

Returns

The submodule referenced by target

Return type

torch.nn.Module

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not an nn.Module

property global_rank: int

The index of the current process across all nodes and devices.

Return type

int

property global_step: int

Total training batches seen across all epochs.

If no Trainer is attached, this propery is 0.

Return type

int

half()

See torch.nn.Module.half().

Return type

Self

property hparams: Union[AttributeDict, MutableMapping]

The collection of hyperparameters saved with save_hyperparameters(). It is mutable by the user. For the frozen set of initial hyperparameters, use hparams_initial.

Return type

Union[AttributeDict, MutableMapping]

Returns

Mutable hyperparameters dictionary

property hparams_initial: AttributeDict

The collection of hyperparameters saved with save_hyperparameters(). These contents are read-only. Manual updates to the saved hyperparameters can instead be performed through hparams.

Returns

immutable initial hyperparameters

Return type

AttributeDict

ipu(device=None)

Move all model parameters and buffers to the IPU.

This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on IPU while being optimized.

Note

This method modifies the module in-place.

Parameters

device (int, optional) – if specified, all parameters will be copied to that device

Returns

self

Return type

Module

load_from_checkpoint(checkpoint_path, map_location=None, hparams_file=None, strict=None, **kwargs)

Primary way of loading a model from a checkpoint. When Lightning saves a checkpoint it stores the arguments passed to __init__ in the checkpoint under "hyper_parameters".

Any arguments specified through **kwargs will override args stored in "hyper_parameters".

Parameters
  • checkpoint_path (Union[str, Path, IO]) – Path to checkpoint. This can also be a URL, or file-like object

  • map_location (Union[device, str, int, Callable[[UntypedStorage, str], Optional[UntypedStorage]], Dict[Union[device, str, int], Union[device, str, int]], None]) – If your checkpoint saved a GPU model and you now load on CPUs or a different number of GPUs, use this to map to the new setup. The behaviour is the same as in torch.load().

  • hparams_file (Union[str, Path, None]) –

    Optional path to a .yaml or .csv file with hierarchical structure as in this example:

    drop_prob: 0.2
    dataloader:
        batch_size: 32
    

    You most likely won’t need this since Lightning will always save the hyperparameters to the checkpoint. However, if your checkpoint weights don’t have the hyperparameters saved, use this method to pass in a .yaml file with the hparams you’d like to use. These will be converted into a dict and passed into your LightningModule for use.

    If your model’s hparams argument is Namespace and .yaml file has hierarchical structure, you need to refactor your model to treat hparams as dict.

  • strict (Optional[bool]) – Whether to strictly enforce that the keys in checkpoint_path match the keys returned by this module’s state dict. Defaults to True unless LightningModule.strict_loading is set, in which case it defaults to the value of LightningModule.strict_loading.

  • **kwargs – Any extra keyword args needed to init the model. Can also be used to override saved hyperparameter values.

Return type

Self

Returns

LightningModule instance with loaded weights and hyperparameters (if available).

Note

load_from_checkpoint is a class method. You should use your LightningModule class to call it instead of the LightningModule instance, or a TypeError will be raised.

Note

To ensure all layers can be loaded from the checkpoint, this function will call configure_model() directly after instantiating the model if this hook is overridden in your LightningModule. However, note that load_from_checkpoint does not support loading sharded checkpoints, and you may run out of memory if the model is too large. In this case, consider loading through the Trainer via .fit(ckpt_path=...).

Example:

# load weights without mapping ...
model = MyLightningModule.load_from_checkpoint('path/to/checkpoint.ckpt')

# or load weights mapping all weights from GPU 1 to GPU 0 ...
map_location = {'cuda:1':'cuda:0'}
model = MyLightningModule.load_from_checkpoint(
    'path/to/checkpoint.ckpt',
    map_location=map_location
)

# or load weights and hyperparameters from separate files.
model = MyLightningModule.load_from_checkpoint(
    'path/to/checkpoint.ckpt',
    hparams_file='/path/to/hparams_file.yaml'
)

# override some of the params with new values
model = MyLightningModule.load_from_checkpoint(
    PATH,
    num_layers=128,
    pretrained_ckpt_path=NEW_PATH,
)

# predict
pretrained_model.eval()
pretrained_model.freeze()
y_hat = pretrained_model(x)
load_state_dict(state_dict, strict=True, assign=False)

Copy parameters and buffers from state_dict into this module and its descendants.

If strict is True, then the keys of state_dict must exactly match the keys returned by this module’s state_dict() function.

Warning

If assign is True the optimizer must be created after the call to load_state_dict.

Parameters
  • state_dict (dict) – a dict containing parameters and persistent buffers.

  • strict (bool, optional) – whether to strictly enforce that the keys in state_dict match the keys returned by this module’s state_dict() function. Default: True

  • assign (bool, optional) – whether to assign items in the state dictionary to their corresponding keys in the module instead of copying them inplace into the module’s current parameters and buffers. When False, the properties of the tensors in the current module are preserved while when True, the properties of the Tensors in the state dict are preserved. Default: False

Returns

  • missing_keys is a list of str containing the missing keys

  • unexpected_keys is a list of str containing the unexpected keys

Return type

NamedTuple with missing_keys and unexpected_keys fields

Note

If a parameter or buffer is registered as None and its corresponding key exists in state_dict, load_state_dict() will raise a RuntimeError.

property local_rank: int

The index of the current process within a single node.

Return type

int

log(name, value, prog_bar=False, logger=None, on_step=None, on_epoch=None, reduce_fx='mean', enable_graph=False, sync_dist=False, sync_dist_group=None, add_dataloader_idx=True, batch_size=None, metric_attribute=None, rank_zero_only=False)

Log a key, value pair.

Example:

self.log('train_loss', loss)

The default behavior per hook is documented here: extensions/logging:Automatic Logging.

Parameters
  • name (str) – key to log.

  • value (Union[Metric, Tensor, int, float]) – value to log. Can be a float, Tensor, or a Metric.

  • prog_bar (bool) – if True logs to the progress bar.

  • logger (Optional[bool]) – if True logs to the logger.

  • on_step (Optional[bool]) – if True logs at this step. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • on_epoch (Optional[bool]) – if True logs epoch accumulated metrics. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • reduce_fx (Union[str, Callable]) – reduction function over step values for end of epoch. torch.mean() by default.

  • enable_graph (bool) – if True, will not auto detach the graph.

  • sync_dist (bool) – if True, reduces the metric across devices. Use with care as this may lead to a significant communication overhead.

  • sync_dist_group (Optional[Any]) – the DDP group to sync across.

  • add_dataloader_idx (bool) – if True, appends the index of the current dataloader to the name (when using multiple dataloaders). If False, user needs to give unique names for each dataloader to not mix the values.

  • batch_size (Optional[int]) – Current batch_size. This will be directly inferred from the loaded batch, but for some data structures you might need to explicitly provide it.

  • metric_attribute (Optional[str]) – To restore the metric state, Lightning requires the reference of the torchmetrics.Metric in your model. This is found automatically if it is a model attribute.

  • rank_zero_only (bool) – Tells Lightning if you are calling self.log from every process (default) or only from rank 0. If True, you won’t be able to use this metric as a monitor in callbacks (e.g., early stopping). Warning: Improper use can lead to deadlocks! See Advanced Logging for more details.

Return type

None

log_dict(dictionary, prog_bar=False, logger=None, on_step=None, on_epoch=None, reduce_fx='mean', enable_graph=False, sync_dist=False, sync_dist_group=None, add_dataloader_idx=True, batch_size=None, rank_zero_only=False)

Log a dictionary of values at once.

Example:

values = {'loss': loss, 'acc': acc, ..., 'metric_n': metric_n}
self.log_dict(values)
Parameters
  • dictionary (Union[Mapping[str, Union[Metric, Tensor, int, float]], MetricCollection]) – key value pairs. The values can be a float, Tensor, Metric, or MetricCollection.

  • prog_bar (bool) – if True logs to the progress base.

  • logger (Optional[bool]) – if True logs to the logger.

  • on_step (Optional[bool]) – if True logs at this step. None auto-logs for training_step but not validation/test_step. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • on_epoch (Optional[bool]) – if True logs epoch accumulated metrics. None auto-logs for val/test step but not training_step. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • reduce_fx (Union[str, Callable]) – reduction function over step values for end of epoch. torch.mean() by default.

  • enable_graph (bool) – if True, will not auto-detach the graph

  • sync_dist (bool) – if True, reduces the metric across GPUs/TPUs. Use with care as this may lead to a significant communication overhead.

  • sync_dist_group (Optional[Any]) – the ddp group to sync across.

  • add_dataloader_idx (bool) – if True, appends the index of the current dataloader to the name (when using multiple). If False, user needs to give unique names for each dataloader to not mix values.

  • batch_size (Optional[int]) – Current batch size. This will be directly inferred from the loaded batch, but some data structures might need to explicitly provide it.

  • rank_zero_only (bool) – Tells Lightning if you are calling self.log from every process (default) or only from rank 0. If True, you won’t be able to use this metric as a monitor in callbacks (e.g., early stopping). Warning: Improper use can lead to deadlocks! See Advanced Logging for more details.

Return type

None

property logger: Optional[Union[Logger, Logger]]

Reference to the logger object in the Trainer.

Return type

Union[Logger, Logger, None]

property loggers: Union[List[Logger], List[Logger]]

Reference to the list of loggers in the Trainer.

Return type

Union[List[Logger], List[Logger]]

lr_scheduler_step(scheduler, metric)

Override this method to adjust the default way the Trainer calls each scheduler. By default, Lightning calls step() and as shown in the example for each scheduler based on its interval.

Parameters
  • scheduler (Union[LRScheduler, ReduceLROnPlateau]) – Learning rate scheduler.

  • metric (Optional[Any]) – Value of the monitor used for schedulers like ReduceLROnPlateau.

Examples:

# DEFAULT
def lr_scheduler_step(self, scheduler, metric):
    if metric is None:
        scheduler.step()
    else:
        scheduler.step(metric)

# Alternative way to update schedulers if it requires an epoch value
def lr_scheduler_step(self, scheduler, metric):
    scheduler.step(epoch=self.current_epoch)
Return type

None

lr_schedulers()

Returns the learning rate scheduler(s) that are being used during training. Useful for manual optimization.

Return type

Union[None, List[Union[LRScheduler, ReduceLROnPlateau]], LRScheduler, ReduceLROnPlateau]

Returns

A single scheduler, or a list of schedulers in case multiple ones are present, or None if no schedulers were returned in configure_optimizers().

manual_backward(loss, *args, **kwargs)

Call this directly from your training_step() when doing optimizations manually. By using this, Lightning can ensure that all the proper scaling gets applied when using mixed precision.

See manual optimization for more examples.

Example:

def training_step(...):
    opt = self.optimizers()
    loss = ...
    opt.zero_grad()
    # automatically applies scaling, etc...
    self.manual_backward(loss)
    opt.step()
Parameters
  • loss (Tensor) – The tensor on which to compute gradients. Must have a graph attached.

  • *args – Additional positional arguments to be forwarded to backward()

  • **kwargs – Additional keyword arguments to be forwarded to backward()

Return type

None

modules()

Return an iterator over all modules in the network.

Yields

Module – a module in the network

Note

Duplicate modules are returned only once. In the following example, l will be returned only once.

Example:

>>> l = nn.Linear(2, 2)
>>> net = nn.Sequential(l, l)
>>> for idx, m in enumerate(net.modules()):
...     print(idx, '->', m)

0 -> Sequential(
  (0): Linear(in_features=2, out_features=2, bias=True)
  (1): Linear(in_features=2, out_features=2, bias=True)
)
1 -> Linear(in_features=2, out_features=2, bias=True)
Return type

Iterator[Module]

named_buffers(prefix='', recurse=True, remove_duplicate=True)

Return an iterator over module buffers, yielding both the name of the buffer as well as the buffer itself.

Parameters
  • prefix (str) – prefix to prepend to all buffer names.

  • recurse (bool, optional) – if True, then yields buffers of this module and all submodules. Otherwise, yields only buffers that are direct members of this module. Defaults to True.

  • remove_duplicate (bool, optional) – whether to remove the duplicated buffers in the result. Defaults to True.

Yields

(str, torch.Tensor) – Tuple containing the name and buffer

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for name, buf in self.named_buffers():
>>>     if name in ['running_var']:
>>>         print(buf.size())
Return type

Iterator[Tuple[str, Tensor]]

named_children()

Return an iterator over immediate children modules, yielding both the name of the module as well as the module itself.

Yields

(str, Module) – Tuple containing a name and child module

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for name, module in model.named_children():
>>>     if name in ['conv4', 'conv5']:
>>>         print(module)
Return type

Iterator[Tuple[str, Module]]

named_modules(memo=None, prefix='', remove_duplicate=True)

Return an iterator over all modules in the network, yielding both the name of the module as well as the module itself.

Parameters
  • memo (Optional[Set[Module]]) – a memo to store the set of modules already added to the result

  • prefix (str) – a prefix that will be added to the name of the module

  • remove_duplicate (bool) – whether to remove the duplicated module instances in the result or not

Yields

(str, Module) – Tuple of name and module

Note

Duplicate modules are returned only once. In the following example, l will be returned only once.

Example:

>>> l = nn.Linear(2, 2)
>>> net = nn.Sequential(l, l)
>>> for idx, m in enumerate(net.named_modules()):
...     print(idx, '->', m)

0 -> ('', Sequential(
  (0): Linear(in_features=2, out_features=2, bias=True)
  (1): Linear(in_features=2, out_features=2, bias=True)
))
1 -> ('0', Linear(in_features=2, out_features=2, bias=True))
named_parameters(prefix='', recurse=True, remove_duplicate=True)

Return an iterator over module parameters, yielding both the name of the parameter as well as the parameter itself.

Parameters
  • prefix (str) – prefix to prepend to all parameter names.

  • recurse (bool) – if True, then yields parameters of this module and all submodules. Otherwise, yields only parameters that are direct members of this module.

  • remove_duplicate (bool, optional) – whether to remove the duplicated parameters in the result. Defaults to True.

Yields

(str, Parameter) – Tuple containing the name and parameter

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for name, param in self.named_parameters():
>>>     if name in ['bias']:
>>>         print(param.size())
Return type

Iterator[Tuple[str, Parameter]]

on_after_backward()

Called after loss.backward() and before optimizers are stepped.

Note

If using native AMP, the gradients will not be unscaled at this point. Use the on_before_optimizer_step if you need the unscaled gradients.

Return type

None

on_after_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch after it is transferred to the device.

Note

To check the current state of execution of this hook you can use self.trainer.training/testing/validating/predicting so that you can add different logic as per your requirement.

Parameters
  • batch (Any) – A batch of data that needs to be altered or augmented.

  • dataloader_idx (int) – The index of the dataloader to which the batch belongs.

Return type

Any

Returns

A batch of data

Example:

def on_after_batch_transfer(self, batch, dataloader_idx):
    batch['x'] = gpu_transforms(batch['x'])
    return batch
Raises

MisconfigurationException – If using IPUs, Trainer(accelerator='ipu').

on_before_backward(loss)

Called before loss.backward().

Parameters

loss (Tensor) – Loss divided by number of batches for gradient accumulation and scaled if using AMP.

Return type

None

on_before_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch before it is transferred to the device.

Note

To check the current state of execution of this hook you can use self.trainer.training/testing/validating/predicting so that you can add different logic as per your requirement.

Parameters
  • batch (Any) – A batch of data that needs to be altered or augmented.

  • dataloader_idx (int) – The index of the dataloader to which the batch belongs.

Return type

Any

Returns

A batch of data

Example:

def on_before_batch_transfer(self, batch, dataloader_idx):
    batch['x'] = transforms(batch['x'])
    return batch
on_before_optimizer_step(optimizer)

Called before optimizer.step().

If using gradient accumulation, the hook is called once the gradients have been accumulated. See: :paramref:`~pytorch_lightning.trainer.trainer.Trainer.accumulate_grad_batches`.

If using AMP, the loss will be unscaled before calling this hook. See these docs for more information on the scaling of gradients.

If clipping gradients, the gradients will not have been clipped yet.

Parameters

optimizer (Optimizer) – Current optimizer being used.

Example:

def on_before_optimizer_step(self, optimizer):
    # example to inspect gradient information in tensorboard
    if self.trainer.global_step % 25 == 0:  # don't make the tf file huge
        for k, v in self.named_parameters():
            self.logger.experiment.add_histogram(
                tag=k, values=v.grad, global_step=self.trainer.global_step
            )
Return type

None

on_before_zero_grad(optimizer)

Called after training_step() and before optimizer.zero_grad().

Called in the training loop after taking an optimizer step and before zeroing grads. Good place to inspect weight information with weights updated.

This is where it is called:

for optimizer in optimizers:
    out = training_step(...)

    model.on_before_zero_grad(optimizer) # < ---- called here
    optimizer.zero_grad()

    backward()
Parameters

optimizer (Optimizer) – The optimizer for which grads should be zeroed.

Return type

None

on_fit_end()

Called at the very end of fit.

If on DDP it is called on every process

Return type

None

on_fit_start()

Called at the very beginning of fit.

If on DDP it is called on every process

Return type

None

property on_gpu: bool

Returns True if this model is currently located on a GPU.

Useful to set flags around the LightningModule for different CPU vs GPU behavior.

Return type

bool

on_load_checkpoint(checkpoint)

Called by Lightning to restore your model. If you saved something with on_save_checkpoint() this is your chance to restore this.

Parameters

checkpoint (Dict[str, Any]) – Loaded checkpoint

Example:

def on_load_checkpoint(self, checkpoint):
    # 99% of the time you don't need to implement this method
    self.something_cool_i_want_to_save = checkpoint['something_cool_i_want_to_save']

Note

Lightning auto-restores global step, epoch, and train state including amp scaling. There is no need for you to restore anything regarding training.

Return type

None

on_predict_batch_end(outputs, batch, batch_idx, dataloader_idx=0)

Called in the predict loop after the batch.

Parameters
  • outputs (Optional[Any]) – The outputs of predict_step(x)

  • batch (Any) – The batched data as it is returned by the prediction DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_predict_batch_start(batch, batch_idx, dataloader_idx=0)

Called in the predict loop before anything happens for that batch.

Parameters
  • batch (Any) – The batched data as it is returned by the test DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_predict_end()

Called at the end of predicting.

Return type

None

on_predict_epoch_end()

Called at the end of predicting.

Return type

None

on_predict_epoch_start()

Called at the beginning of predicting.

Return type

None

on_predict_model_eval()

Called when the predict loop starts.

The predict loop by default calls .eval() on the LightningModule before it starts. Override this hook to change the behavior.

Return type

None

on_predict_start()

Called at the beginning of predicting.

Return type

None

on_save_checkpoint(checkpoint)

Called by Lightning when saving a checkpoint to give you a chance to store anything else you might want to save.

Parameters

checkpoint (Dict[str, Any]) – The full checkpoint dictionary before it gets dumped to a file. Implementations of this hook can insert additional data into this dictionary.

Example:

def on_save_checkpoint(self, checkpoint):
    # 99% of use cases you don't need to implement this method
    checkpoint['something_cool_i_want_to_save'] = my_cool_pickable_object

Note

Lightning saves all aspects of training (epoch, global step, etc…) including amp scaling. There is no need for you to store anything about training.

Return type

None

on_test_batch_end(outputs, batch, batch_idx, dataloader_idx=0)

Called in the test loop after the batch.

Parameters
  • outputs (Union[Tensor, Mapping[str, Any], None]) – The outputs of test_step(x)

  • batch (Any) – The batched data as it is returned by the test DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_test_batch_start(batch, batch_idx, dataloader_idx=0)

Called in the test loop before anything happens for that batch.

Parameters
  • batch (Any) – The batched data as it is returned by the test DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_test_end()

Called at the end of testing.

Return type

None

on_test_epoch_end()

Called in the test loop at the very end of the epoch.

Return type

None

on_test_epoch_start()

Called in the test loop at the very beginning of the epoch.

Return type

None

on_test_model_eval()

Called when the test loop starts.

The test loop by default calls .eval() on the LightningModule before it starts. Override this hook to change the behavior. See also on_test_model_train().

Return type

None

on_test_model_train()

Called when the test loop ends.

The test loop by default restores the training mode of the LightningModule to what it was before starting testing. Override this hook to change the behavior. See also on_test_model_eval().

Return type

None

on_test_start()

Called at the beginning of testing.

Return type

None

on_train_batch_end(outputs, batch, batch_idx)

Called in the training loop after the batch.

Parameters
  • outputs (Union[Tensor, Mapping[str, Any], None]) – The outputs of training_step(x)

  • batch (Any) – The batched data as it is returned by the training DataLoader.

  • batch_idx (int) – the index of the batch

Return type

None

on_train_batch_start(batch, batch_idx)

Called in the training loop before anything happens for that batch.

If you return -1 here, you will skip training for the rest of the current epoch.

Parameters
  • batch (Any) – The batched data as it is returned by the training DataLoader.

  • batch_idx (int) – the index of the batch

Return type

Optional[int]

on_train_end()

Called at the end of training before logger experiment is closed.

Return type

None

on_train_epoch_end()

Called in the training loop at the very end of the epoch.

To access all batch outputs at the end of the epoch, you can cache step outputs as an attribute of the LightningModule and access them in this hook:

class MyLightningModule(L.LightningModule):
    def __init__(self):
        super().__init__()
        self.training_step_outputs = []

    def training_step(self):
        loss = ...
        self.training_step_outputs.append(loss)
        return loss

    def on_train_epoch_end(self):
        # do something with all training_step outputs, for example:
        epoch_mean = torch.stack(self.training_step_outputs).mean()
        self.log("training_epoch_mean", epoch_mean)
        # free up the memory
        self.training_step_outputs.clear()
Return type

None

on_train_epoch_start()

Called in the training loop at the very beginning of the epoch.

Return type

None

on_train_start()

Called at the beginning of training after sanity check.

Return type

None

on_validation_batch_end(outputs, batch, batch_idx, dataloader_idx=0)

Called in the validation loop after the batch.

Parameters
  • outputs (Union[Tensor, Mapping[str, Any], None]) – The outputs of validation_step(x)

  • batch (Any) – The batched data as it is returned by the validation DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_validation_batch_start(batch, batch_idx, dataloader_idx=0)

Called in the validation loop before anything happens for that batch.

Parameters
  • batch (Any) – The batched data as it is returned by the validation DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_validation_end()

Called at the end of validation.

Return type

None

on_validation_epoch_end()

Called in the validation loop at the very end of the epoch.

Return type

None

on_validation_epoch_start()

Called in the validation loop at the very beginning of the epoch.

Return type

None

on_validation_model_eval()

Called when the validation loop starts.

The validation loop by default calls .eval() on the LightningModule before it starts. Override this hook to change the behavior. See also on_validation_model_train().

Return type

None

on_validation_model_train()

Called when the validation loop ends.

The validation loop by default restores the training mode of the LightningModule to what it was before starting validation. Override this hook to change the behavior. See also on_validation_model_eval().

Return type

None

on_validation_model_zero_grad()

Called by the training loop to release gradients before entering the validation loop.

Return type

None

on_validation_start()

Called at the beginning of validation.

Return type

None

optimizer_step(epoch, batch_idx, optimizer, optimizer_closure=None)

Override this method to adjust the default way the Trainer calls the optimizer.

By default, Lightning calls step() and zero_grad() as shown in the example. This method (and zero_grad()) won’t be called during the accumulation phase when Trainer(accumulate_grad_batches != 1). Overriding this hook has no benefit with manual optimization.

Parameters
  • epoch (int) – Current epoch

  • batch_idx (int) – Index of current batch

  • optimizer (Union[Optimizer, LightningOptimizer]) – A PyTorch optimizer

  • optimizer_closure (Optional[Callable[[], Any]]) – The optimizer closure. This closure must be executed as it includes the calls to training_step(), optimizer.zero_grad(), and backward().

Examples:

# DEFAULT
def optimizer_step(self, epoch, batch_idx, optimizer, optimizer_closure):
    optimizer.step(closure=optimizer_closure)

# Learning rate warm-up
def optimizer_step(self, epoch, batch_idx, optimizer, optimizer_closure):
    # update params
    optimizer.step(closure=optimizer_closure)

    # manually warm up lr without a scheduler
    if self.trainer.global_step < 500:
        lr_scale = min(1.0, float(self.trainer.global_step + 1) / 500.0)
        for pg in optimizer.param_groups:
            pg["lr"] = lr_scale * self.learning_rate
Return type

None

optimizer_zero_grad(epoch, batch_idx, optimizer)

Override this method to change the default behaviour of optimizer.zero_grad().

Parameters
  • epoch (int) – Current epoch

  • batch_idx (int) – Index of current batch

  • optimizer (Optimizer) – A PyTorch optimizer

Examples:

# DEFAULT
def optimizer_zero_grad(self, epoch, batch_idx, optimizer):
    optimizer.zero_grad()

# Set gradients to `None` instead of zero to improve performance (not required on `torch>=2.0.0`).
def optimizer_zero_grad(self, epoch, batch_idx, optimizer):
    optimizer.zero_grad(set_to_none=True)

See torch.optim.Optimizer.zero_grad() for the explanation of the above example.

Return type

None

optimizers(use_pl_optimizer=True)

Returns the optimizer(s) that are being used during training. Useful for manual optimization.

Parameters

use_pl_optimizer (bool) – If True, will wrap the optimizer(s) in a LightningOptimizer for automatic handling of precision, profiling, and counting of step calls for proper logging and checkpointing. It specifically wraps the step method and custom optimizers that don’t have this method are not supported.

Return type

Union[Optimizer, LightningOptimizer, _FabricOptimizer, List[Optimizer], List[LightningOptimizer], List[_FabricOptimizer]]

Returns

A single optimizer, or a list of optimizers in case multiple ones are present.

property output_chunk_length: Optional[int]

Number of time steps predicted at once by the model.

Return type

Optional[int]

parameters(recurse=True)

Return an iterator over module parameters.

This is typically passed to an optimizer.

Parameters

recurse (bool) – if True, then yields parameters of this module and all submodules. Otherwise, yields only parameters that are direct members of this module.

Yields

Parameter – module parameter

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for param in model.parameters():
>>>     print(type(param), param.size())
<class 'torch.Tensor'> (20L,)
<class 'torch.Tensor'> (20L, 1L, 5L, 5L)
Return type

Iterator[Parameter]

predict_dataloader()

An iterable or collection of iterables specifying prediction samples.

For more information about multiple dataloaders, see this section.

It’s recommended that all data downloads and preparation happen in prepare_data().

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware There is no need to set it yourself.

Return type

Any

Returns

A torch.utils.data.DataLoader or a sequence of them specifying prediction samples.

predict_step(batch, batch_idx, dataloader_idx=None)

performs the prediction step

batch

output of Darts’ InferenceDataset - tuple of (past_target, past_covariates, historic_future_covariates, future_covariates, future_past_covariates, input time series, prediction start time step)

batch_idx

the batch index of the current batch

dataloader_idx

the dataloader index

Return type

Sequence[TimeSeries]

prepare_data()

Use this to download and prepare data. Downloading and saving data with multiple processes (distributed settings) will result in corrupted data. Lightning ensures this method is called only within a single process, so you can safely add your downloading logic within.

Warning

DO NOT set state to the model (use setup instead) since this is NOT called on every device

Example:

def prepare_data(self):
    # good
    download_data()
    tokenize()
    etc()

    # bad
    self.split = data_split
    self.some_state = some_other_state()

In a distributed environment, prepare_data can be called in two ways (using prepare_data_per_node)

  1. Once per node. This is the default and is only called on LOCAL_RANK=0.

  2. Once in total. Only called on GLOBAL_RANK=0.

Example:

# DEFAULT
# called once per node on LOCAL_RANK=0 of that node
class LitDataModule(LightningDataModule):
    def __init__(self):
        super().__init__()
        self.prepare_data_per_node = True

# call on GLOBAL_RANK=0 (great for shared file systems)
class LitDataModule(LightningDataModule):
    def __init__(self):
        super().__init__()
        self.prepare_data_per_node = False

This is called before requesting the dataloaders:

model.prepare_data()
initialize_distributed()
model.setup(stage)
model.train_dataloader()
model.val_dataloader()
model.test_dataloader()
model.predict_dataloader()
Return type

None

print(*args, **kwargs)

Prints only from process 0. Use this in any distributed mode to log only once.

Parameters
  • *args – The thing to print. The same as for Python’s built-in print function.

  • **kwargs – The same as for Python’s built-in print function.

Example:

def forward(self, x):
    self.print(x, 'in forward')
Return type

None

register_backward_hook(hook)

Register a backward hook on the module.

This function is deprecated in favor of register_full_backward_hook() and the behavior of this function will change in future versions.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_buffer(name, tensor, persistent=True)

Add a buffer to the module.

This is typically used to register a buffer that should not to be considered a model parameter. For example, BatchNorm’s running_mean is not a parameter, but is part of the module’s state. Buffers, by default, are persistent and will be saved alongside parameters. This behavior can be changed by setting persistent to False. The only difference between a persistent buffer and a non-persistent buffer is that the latter will not be a part of this module’s state_dict.

Buffers can be accessed as attributes using given names.

Parameters
  • name (str) – name of the buffer. The buffer can be accessed from this module using the given name

  • tensor (Tensor or None) – buffer to be registered. If None, then operations that run on buffers, such as cuda, are ignored. If None, the buffer is not included in the module’s state_dict.

  • persistent (bool) – whether the buffer is part of this module’s state_dict.

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> self.register_buffer('running_mean', torch.zeros(num_features))
Return type

None

register_forward_hook(hook, *, prepend=False, with_kwargs=False, always_call=False)

Register a forward hook on the module.

The hook will be called every time after forward() has computed an output.

If with_kwargs is False or not specified, the input contains only the positional arguments given to the module. Keyword arguments won’t be passed to the hooks and only to the forward. The hook can modify the output. It can modify the input inplace but it will not have effect on forward since this is called after forward() is called. The hook should have the following signature:

hook(module, args, output) -> None or modified output

If with_kwargs is True, the forward hook will be passed the kwargs given to the forward function and be expected to return the output possibly modified. The hook should have the following signature:

hook(module, args, kwargs, output) -> None or modified output
Parameters
  • hook (Callable) – The user defined hook to be registered.

  • prepend (bool) – If True, the provided hook will be fired before all existing forward hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing forward hooks on this torch.nn.modules.Module. Note that global forward hooks registered with register_module_forward_hook() will fire before all hooks registered by this method. Default: False

  • with_kwargs (bool) – If True, the hook will be passed the kwargs given to the forward function. Default: False

  • always_call (bool) – If True the hook will be run regardless of whether an exception is raised while calling the Module. Default: False

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_forward_pre_hook(hook, *, prepend=False, with_kwargs=False)

Register a forward pre-hook on the module.

The hook will be called every time before forward() is invoked.

If with_kwargs is false or not specified, the input contains only the positional arguments given to the module. Keyword arguments won’t be passed to the hooks and only to the forward. The hook can modify the input. User can either return a tuple or a single modified value in the hook. We will wrap the value into a tuple if a single value is returned (unless that value is already a tuple). The hook should have the following signature:

hook(module, args) -> None or modified input

If with_kwargs is true, the forward pre-hook will be passed the kwargs given to the forward function. And if the hook modifies the input, both the args and kwargs should be returned. The hook should have the following signature:

hook(module, args, kwargs) -> None or a tuple of modified input and kwargs
Parameters
  • hook (Callable) – The user defined hook to be registered.

  • prepend (bool) – If true, the provided hook will be fired before all existing forward_pre hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing forward_pre hooks on this torch.nn.modules.Module. Note that global forward_pre hooks registered with register_module_forward_pre_hook() will fire before all hooks registered by this method. Default: False

  • with_kwargs (bool) – If true, the hook will be passed the kwargs given to the forward function. Default: False

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_full_backward_hook(hook, prepend=False)

Register a backward hook on the module.

The hook will be called every time the gradients with respect to a module are computed, i.e. the hook will execute if and only if the gradients with respect to module outputs are computed. The hook should have the following signature:

hook(module, grad_input, grad_output) -> tuple(Tensor) or None

The grad_input and grad_output are tuples that contain the gradients with respect to the inputs and outputs respectively. The hook should not modify its arguments, but it can optionally return a new gradient with respect to the input that will be used in place of grad_input in subsequent computations. grad_input will only correspond to the inputs given as positional arguments and all kwarg arguments are ignored. Entries in grad_input and grad_output will be None for all non-Tensor arguments.

For technical reasons, when this hook is applied to a Module, its forward function will receive a view of each Tensor passed to the Module. Similarly the caller will receive a view of each Tensor returned by the Module’s forward function.

Warning

Modifying inputs or outputs inplace is not allowed when using backward hooks and will raise an error.

Parameters
  • hook (Callable) – The user-defined hook to be registered.

  • prepend (bool) – If true, the provided hook will be fired before all existing backward hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing backward hooks on this torch.nn.modules.Module. Note that global backward hooks registered with register_module_full_backward_hook() will fire before all hooks registered by this method.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_full_backward_pre_hook(hook, prepend=False)

Register a backward pre-hook on the module.

The hook will be called every time the gradients for the module are computed. The hook should have the following signature:

hook(module, grad_output) -> tuple[Tensor] or None

The grad_output is a tuple. The hook should not modify its arguments, but it can optionally return a new gradient with respect to the output that will be used in place of grad_output in subsequent computations. Entries in grad_output will be None for all non-Tensor arguments.

For technical reasons, when this hook is applied to a Module, its forward function will receive a view of each Tensor passed to the Module. Similarly the caller will receive a view of each Tensor returned by the Module’s forward function.

Warning

Modifying inputs inplace is not allowed when using backward hooks and will raise an error.

Parameters
  • hook (Callable) – The user-defined hook to be registered.

  • prepend (bool) – If true, the provided hook will be fired before all existing backward_pre hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing backward_pre hooks on this torch.nn.modules.Module. Note that global backward_pre hooks registered with register_module_full_backward_pre_hook() will fire before all hooks registered by this method.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_load_state_dict_post_hook(hook)

Register a post hook to be run after module’s load_state_dict is called.

It should have the following signature::

hook(module, incompatible_keys) -> None

The module argument is the current module that this hook is registered on, and the incompatible_keys argument is a NamedTuple consisting of attributes missing_keys and unexpected_keys. missing_keys is a list of str containing the missing keys and unexpected_keys is a list of str containing the unexpected keys.

The given incompatible_keys can be modified inplace if needed.

Note that the checks performed when calling load_state_dict() with strict=True are affected by modifications the hook makes to missing_keys or unexpected_keys, as expected. Additions to either set of keys will result in an error being thrown when strict=True, and clearing out both missing and unexpected keys will avoid an error.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_module(name, module)

Alias for add_module().

Return type

None

register_parameter(name, param)

Add a parameter to the module.

The parameter can be accessed as an attribute using given name.

Parameters
  • name (str) – name of the parameter. The parameter can be accessed from this module using the given name

  • param (Parameter or None) – parameter to be added to the module. If None, then operations that run on parameters, such as cuda, are ignored. If None, the parameter is not included in the module’s state_dict.

Return type

None

register_state_dict_pre_hook(hook)

Register a pre-hook for the load_state_dict() method.

These hooks will be called with arguments: self, prefix, and keep_vars before calling state_dict on self. The registered hooks can be used to perform pre-processing before the state_dict call is made.

requires_grad_(requires_grad=True)

Change if autograd should record operations on parameters in this module.

This method sets the parameters’ requires_grad attributes in-place.

This method is helpful for freezing part of the module for finetuning or training parts of a model individually (e.g., GAN training).

See locally-disable-grad-doc for a comparison between .requires_grad_() and several similar mechanisms that may be confused with it.

Parameters

requires_grad (bool) – whether autograd should record operations on parameters in this module. Default: True.

Returns

self

Return type

Module

save_hyperparameters(*args, ignore=None, frame=None, logger=True)

Save arguments to hparams attribute.

Parameters
  • args (Any) – single object of dict, NameSpace or OmegaConf or string names or arguments from class __init__

  • ignore (Union[str, Sequence[str], None]) – an argument name or a list of argument names from class __init__ to be ignored

  • frame (Optional[frame]) – a frame object. Default is None

  • logger (bool) – Whether to send the hyperparameters to the logger. Default: True

Example::
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class ManuallyArgsModel(HyperparametersMixin):
...     def __init__(self, arg1, arg2, arg3):
...         super().__init__()
...         # manually assign arguments
...         self.save_hyperparameters('arg1', 'arg3')
...     def forward(self, *args, **kwargs):
...         ...
>>> model = ManuallyArgsModel(1, 'abc', 3.14)
>>> model.hparams
"arg1": 1
"arg3": 3.14
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class AutomaticArgsModel(HyperparametersMixin):
...     def __init__(self, arg1, arg2, arg3):
...         super().__init__()
...         # equivalent automatic
...         self.save_hyperparameters()
...     def forward(self, *args, **kwargs):
...         ...
>>> model = AutomaticArgsModel(1, 'abc', 3.14)
>>> model.hparams
"arg1": 1
"arg2": abc
"arg3": 3.14
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class SingleArgModel(HyperparametersMixin):
...     def __init__(self, params):
...         super().__init__()
...         # manually assign single argument
...         self.save_hyperparameters(params)
...     def forward(self, *args, **kwargs):
...         ...
>>> model = SingleArgModel(Namespace(p1=1, p2='abc', p3=3.14))
>>> model.hparams
"p1": 1
"p2": abc
"p3": 3.14
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class ManuallyArgsModel(HyperparametersMixin):
...     def __init__(self, arg1, arg2, arg3):
...         super().__init__()
...         # pass argument(s) to ignore as a string or in a list
...         self.save_hyperparameters(ignore='arg2')
...     def forward(self, *args, **kwargs):
...         ...
>>> model = ManuallyArgsModel(1, 'abc', 3.14)
>>> model.hparams
"arg1": 1
"arg3": 3.14
Return type

None

set_extra_state(state)

Set extra state contained in the loaded state_dict.

This function is called from load_state_dict() to handle any extra state found within the state_dict. Implement this function and a corresponding get_extra_state() for your module if you need to store extra state within its state_dict.

Parameters

state (dict) – Extra state from the state_dict

set_mc_dropout(active)
set_predict_parameters(n, num_samples, roll_size, batch_size, n_jobs, predict_likelihood_parameters, mc_dropout)

to be set from TorchForecastingModel before calling trainer.predict() and reset at self.on_predict_end()

Return type

None

setup(stage)

Called at the beginning of fit (train + validate), validate, test, or predict. This is a good hook when you need to build models dynamically or adjust something about them. This hook is called on every process when using DDP.

Parameters

stage (str) – either 'fit', 'validate', 'test', or 'predict'

Example:

class LitModel(...):
    def __init__(self):
        self.l1 = None

    def prepare_data(self):
        download_data()
        tokenize()

        # don't do this
        self.something = else

    def setup(self, stage):
        data = load_data(...)
        self.l1 = nn.Linear(28, data.num_classes)
Return type

None

share_memory()

See torch.Tensor.share_memory_().

Return type

~T

state_dict(*args, destination=None, prefix='', keep_vars=False)

Return a dictionary containing references to the whole state of the module.

Both parameters and persistent buffers (e.g. running averages) are included. Keys are corresponding parameter and buffer names. Parameters and buffers set to None are not included.

Note

The returned object is a shallow copy. It contains references to the module’s parameters and buffers.

Warning

Currently state_dict() also accepts positional arguments for destination, prefix and keep_vars in order. However, this is being deprecated and keyword arguments will be enforced in future releases.

Warning

Please avoid the use of argument destination as it is not designed for end-users.

Parameters
  • destination (dict, optional) – If provided, the state of module will be updated into the dict and the same object is returned. Otherwise, an OrderedDict will be created and returned. Default: None.

  • prefix (str, optional) – a prefix added to parameter and buffer names to compose the keys in state_dict. Default: ''.

  • keep_vars (bool, optional) – by default the Tensor s returned in the state dict are detached from autograd. If it’s set to True, detaching will not be performed. Default: False.

Returns

a dictionary containing a whole state of the module

Return type

dict

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> module.state_dict().keys()
['bias', 'weight']
property strict_loading: bool

Determines how Lightning loads this model using .load_state_dict(…, strict=model.strict_loading).

Return type

bool

property supports_probabilistic_prediction: bool
Return type

bool

teardown(stage)

Called at the end of fit (train + validate), validate, test, or predict.

Parameters

stage (str) – either 'fit', 'validate', 'test', or 'predict'

Return type

None

test_dataloader()

An iterable or collection of iterables specifying test samples.

For more information about multiple dataloaders, see this section.

For data processing use the following pattern:

However, the above are only necessary for distributed processing.

Warning

do not assign state in prepare_data

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware. There is no need to set it yourself.

Note

If you don’t need a test dataset and a test_step(), you don’t need to implement this method.

Return type

Any

test_step(*args, **kwargs)

Operates on a single batch of data from the test set. In this step you’d normally generate examples or calculate anything of interest such as accuracy.

Parameters
  • batch – The output of your data iterable, normally a DataLoader.

  • batch_idx – The index of this batch.

  • dataloader_idx – The index of the dataloader that produced this batch. (only if multiple dataloaders used)

Return type

Union[Tensor, Mapping[str, Any], None]

Returns

  • Tensor - The loss tensor

  • dict - A dictionary. Can include any keys, but must include the key 'loss'.

  • None - Skip to the next batch.

# if you have one test dataloader:
def test_step(self, batch, batch_idx): ...

# if you have multiple test dataloaders:
def test_step(self, batch, batch_idx, dataloader_idx=0): ...

Examples:

# CASE 1: A single test dataset
def test_step(self, batch, batch_idx):
    x, y = batch

    # implement your own
    out = self(x)
    loss = self.loss(out, y)

    # log 6 example images
    # or generated text... or whatever
    sample_imgs = x[:6]
    grid = torchvision.utils.make_grid(sample_imgs)
    self.logger.experiment.add_image('example_images', grid, 0)

    # calculate acc
    labels_hat = torch.argmax(out, dim=1)
    test_acc = torch.sum(y == labels_hat).item() / (len(y) * 1.0)

    # log the outputs!
    self.log_dict({'test_loss': loss, 'test_acc': test_acc})

If you pass in multiple test dataloaders, test_step() will have an additional argument. We recommend setting the default value of 0 so that you can quickly switch between single and multiple dataloaders.

# CASE 2: multiple test dataloaders
def test_step(self, batch, batch_idx, dataloader_idx=0):
    # dataloader_idx tells you which dataset this is.
    ...

Note

If you don’t need to test you don’t need to implement this method.

Note

When the test_step() is called, the model has been put in eval mode and PyTorch gradients have been disabled. At the end of the test epoch, the model goes back to training mode and gradients are enabled.

to(*args, **kwargs)

See torch.nn.Module.to().

Return type

Self

to_dtype(dtype)

Cast module precision (float32 by default) to another precision.

to_empty(*, device, recurse=True)

Move the parameters and buffers to the specified device without copying storage.

Parameters
  • device (torch.device) – The desired device of the parameters and buffers in this module.

  • recurse (bool) – Whether parameters and buffers of submodules should be recursively moved to the specified device.

Returns

self

Return type

Module

to_onnx(file_path, input_sample=None, **kwargs)

Saves the model in ONNX format.

Parameters
  • file_path (Union[str, Path]) – The path of the file the onnx model should be saved to.

  • input_sample (Optional[Any]) – An input for tracing. Default: None (Use self.example_input_array)

  • **kwargs – Will be passed to torch.onnx.export function.

Example:

class SimpleModel(LightningModule):
    def __init__(self):
        super().__init__()
        self.l1 = torch.nn.Linear(in_features=64, out_features=4)

    def forward(self, x):
        return torch.relu(self.l1(x.view(x.size(0), -1)

model = SimpleModel()
input_sample = torch.randn(1, 64)
model.to_onnx("export.onnx", input_sample, export_params=True)
Return type

None

to_torchscript(file_path=None, method='script', example_inputs=None, **kwargs)

By default compiles the whole model to a ScriptModule. If you want to use tracing, please provided the argument method='trace' and make sure that either the example_inputs argument is provided, or the model has example_input_array set. If you would like to customize the modules that are scripted you should override this method. In case you want to return multiple modules, we recommend using a dictionary.

Parameters
  • file_path (Union[str, Path, None]) – Path where to save the torchscript. Default: None (no file saved).

  • method (Optional[str]) – Whether to use TorchScript’s script or trace method. Default: ‘script’

  • example_inputs (Optional[Any]) – An input to be used to do tracing when method is set to ‘trace’. Default: None (uses example_input_array)

  • **kwargs – Additional arguments that will be passed to the torch.jit.script() or torch.jit.trace() function.

Note

  • Requires the implementation of the forward() method.

  • The exported script will be set to evaluation mode.

  • It is recommended that you install the latest supported version of PyTorch to use this feature without limitations. See also the torch.jit documentation for supported features.

Example:

class SimpleModel(LightningModule):
    def __init__(self):
        super().__init__()
        self.l1 = torch.nn.Linear(in_features=64, out_features=4)

    def forward(self, x):
        return torch.relu(self.l1(x.view(x.size(0), -1)))

model = SimpleModel()
model.to_torchscript(file_path="model.pt")

torch.jit.save(model.to_torchscript(
    file_path="model_trace.pt", method='trace', example_inputs=torch.randn(1, 64))
)
Return type

Union[ScriptModule, Dict[str, ScriptModule]]

Returns

This LightningModule as a torchscript, regardless of whether file_path is defined or not.

toggle_optimizer(optimizer)

Makes sure only the gradients of the current optimizer’s parameters are calculated in the training step to prevent dangling gradients in multiple-optimizer setup.

It works with untoggle_optimizer() to make sure param_requires_grad_state is properly reset.

Parameters

optimizer (Union[Optimizer, LightningOptimizer]) – The optimizer to toggle.

Return type

None

train(mode=True)

Set the module in training mode.

This has any effect only on certain modules. See documentations of particular modules for details of their behaviors in training/evaluation mode, if they are affected, e.g. Dropout, BatchNorm, etc.

Parameters

mode (bool) – whether to set training mode (True) or evaluation mode (False). Default: True.

Returns

self

Return type

Module

train_dataloader()

An iterable or collection of iterables specifying training samples.

For more information about multiple dataloaders, see this section.

The dataloader you return will not be reloaded unless you set :paramref:`~pytorch_lightning.trainer.trainer.Trainer.reload_dataloaders_every_n_epochs` to a positive integer.

For data processing use the following pattern:

However, the above are only necessary for distributed processing.

Warning

do not assign state in prepare_data

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware. There is no need to set it yourself.

Return type

Any

property trainer: Trainer
Return type

Trainer

training: bool
training_step(train_batch, batch_idx)

performs the training step

Return type

Tensor

transfer_batch_to_device(batch, device, dataloader_idx)

Override this hook if your DataLoader returns tensors wrapped in a custom data structure.

The data types listed below (and any arbitrary nesting of them) are supported out of the box:

  • torch.Tensor or anything that implements .to(…)

  • list

  • dict

  • tuple

For anything else, you need to define how the data is moved to the target device (CPU, GPU, TPU, …).

Note

This hook should only transfer the data and not modify it, nor should it move the data to any other device than the one passed in as argument (unless you know what you are doing). To check the current state of execution of this hook you can use self.trainer.training/testing/validating/predicting so that you can add different logic as per your requirement.

Parameters
  • batch (Any) – A batch of data that needs to be transferred to a new device.

  • device (device) – The target device as defined in PyTorch.

  • dataloader_idx (int) – The index of the dataloader to which the batch belongs.

Return type

Any

Returns

A reference to the data on the new device.

Example:

def transfer_batch_to_device(self, batch, device, dataloader_idx):
    if isinstance(batch, CustomBatch):
        # move all tensors in your custom data structure to the device
        batch.samples = batch.samples.to(device)
        batch.targets = batch.targets.to(device)
    elif dataloader_idx == 0:
        # skip device transfer for the first dataloader or anything you wish
        pass
    else:
        batch = super().transfer_batch_to_device(batch, device, dataloader_idx)
    return batch
Raises

MisconfigurationException – If using IPUs, Trainer(accelerator='ipu').

See also

  • move_data_to_device()

  • apply_to_collection()

type(dst_type)

See torch.nn.Module.type().

Return type

Self

unfreeze()

Unfreeze all parameters for training.

model = MyLightningModule(...)
model.unfreeze()
Return type

None

untoggle_optimizer(optimizer)

Resets the state of required gradients that were toggled with toggle_optimizer().

Parameters

optimizer (Union[Optimizer, LightningOptimizer]) – The optimizer to untoggle.

Return type

None

val_dataloader()

An iterable or collection of iterables specifying validation samples.

For more information about multiple dataloaders, see this section.

The dataloader you return will not be reloaded unless you set :paramref:`~pytorch_lightning.trainer.trainer.Trainer.reload_dataloaders_every_n_epochs` to a positive integer.

It’s recommended that all data downloads and preparation happen in prepare_data().

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware There is no need to set it yourself.

Note

If you don’t need a validation dataset and a validation_step(), you don’t need to implement this method.

Return type

Any

validation_step(val_batch, batch_idx)

performs the validation step

Return type

Tensor

xpu(device=None)

Move all model parameters and buffers to the XPU.

This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on XPU while being optimized.

Note

This method modifies the module in-place.

Parameters

device (int, optional) – if specified, all parameters will be copied to that device

Returns

self

Return type

Module

zero_grad(set_to_none=True)

Reset gradients of all model parameters.

See similar function under torch.optim.Optimizer for more context.

Parameters

set_to_none (bool) – instead of setting to zero, set the grads to None. See torch.optim.Optimizer.zero_grad() for details.

Return type

None

class darts.models.forecasting.pl_forecasting_module.PLForecastingModule(input_chunk_length, output_chunk_length, output_chunk_shift=0, train_sample_shape=None, loss_fn=MSELoss(), torch_metrics=None, likelihood=None, optimizer_cls=<class 'torch.optim.adam.Adam'>, optimizer_kwargs=None, lr_scheduler_cls=None, lr_scheduler_kwargs=None, use_reversible_instance_norm=False)[source]

Bases: LightningModule, ABC

PyTorch Lightning-based Forecasting Module.

This class is meant to be inherited to create a new PyTorch Lightning-based forecasting module. When subclassing this class, please make sure to add the following methods with the given signatures:

  • PLForecastingModule.__init__()

  • PLForecastingModule.forward()

  • PLForecastingModule._produce_train_output()

  • PLForecastingModule._get_batch_prediction()

In subclass MyModel’s __init__() function call super(MyModel, self).__init__(**kwargs) where kwargs are the parameters of PLForecastingModule.

Parameters
  • input_chunk_length (int) – Number of time steps in the past to take as a model input (per chunk). Applies to the target series, and past and/or future covariates (if the model supports it).

  • output_chunk_length (int) – Number of time steps predicted at once (per chunk) by the internal model. Also, the number of future values from future covariates to use as a model input (if the model supports future covariates). It is not the same as forecast horizon n used in predict(), which is the desired number of prediction points generated using either a one-shot- or autoregressive forecast. Setting n <= output_chunk_length prevents auto-regression. This is useful when the covariates don’t extend far enough into the future, or to prohibit the model from using future values of past and / or future covariates for prediction (depending on the model’s covariate support).

  • train_sample_shape (Optional[Tuple]) – Shape of the model’s input, used to instantiate model without calling fit_from_dataset and perform sanity check on new training/inference datasets used for re-training or prediction.

  • loss_fn (_Loss) – PyTorch loss function used for training. This parameter will be ignored for probabilistic models if the likelihood parameter is specified. Default: torch.nn.MSELoss().

  • torch_metrics (Union[Metric, MetricCollection, None]) – A torch metric or a MetricCollection used for evaluation. A full list of available metrics can be found at https://torchmetrics.readthedocs.io/en/latest/. Default: None.

  • likelihood (Optional[Likelihood]) – One of Darts’ Likelihood models to be used for probabilistic forecasts. Default: None.

  • optimizer_cls (Optimizer) – The PyTorch optimizer class to be used. Default: torch.optim.Adam.

  • optimizer_kwargs (Optional[Dict]) – Optionally, some keyword arguments for the PyTorch optimizer (e.g., {'lr': 1e-3} for specifying a learning rate). Otherwise the default values of the selected optimizer_cls will be used. Default: None.

  • lr_scheduler_cls (Optional[_LRScheduler]) – Optionally, the PyTorch learning rate scheduler class to be used. Specifying None corresponds to using a constant learning rate. Default: None.

  • lr_scheduler_kwargs (Optional[Dict]) – Optionally, some keyword arguments for the PyTorch learning rate scheduler. Default: None.

  • use_reversible_instance_norm (bool) – Whether to use reversible instance normalization RINorm against distribution shift as shown in [1]. It is only applied to the features of the target series and not the covariates.

References

1

T. Kim et al. “Reversible Instance Normalization for Accurate Time-Series Forecasting against Distribution Shift”, https://openreview.net/forum?id=cGDAkQo1C0p

Attributes

automatic_optimization

If set to False you are responsible for calling .backward(), .step(), .zero_grad().

current_epoch

The current epoch in the Trainer, or 0 if not attached.

example_input_array

The example input array is a specification of what the module can consume in the forward() method.

global_rank

The index of the current process across all nodes and devices.

global_step

Total training batches seen across all epochs.

hparams

The collection of hyperparameters saved with save_hyperparameters().

hparams_initial

The collection of hyperparameters saved with save_hyperparameters().

local_rank

The index of the current process within a single node.

logger

Reference to the logger object in the Trainer.

loggers

Reference to the list of loggers in the Trainer.

on_gpu

Returns True if this model is currently located on a GPU.

output_chunk_length

Number of time steps predicted at once by the model.

strict_loading

Determines how Lightning loads this model using .load_state_dict(..., strict=model.strict_loading).

device

dtype

epochs_trained

fabric

supports_probabilistic_prediction

trainer

Methods

add_module(name, module)

Add a child module to the current module.

all_gather(data[, group, sync_grads])

Gather tensors or collections of tensors from multiple processes.

apply(fn)

Apply fn recursively to every submodule (as returned by .children()) as well as self.

backward(loss, *args, **kwargs)

Called to perform backward on the loss returned in training_step().

bfloat16()

Casts all floating point parameters and buffers to bfloat16 datatype.

buffers([recurse])

Return an iterator over module buffers.

children()

Return an iterator over immediate children modules.

clip_gradients(optimizer[, ...])

Handles gradient clipping internally.

compile(*args, **kwargs)

Compile this Module's forward using torch.compile().

configure_callbacks()

Configure model-specific callbacks.

configure_gradient_clipping(optimizer[, ...])

Perform gradient clipping for the optimizer parameters.

configure_model()

Hook to create modules in a strategy and precision aware context.

configure_optimizers()

configures optimizers and learning rate schedulers for model optimization.

configure_sharded_model()

Deprecated.

configure_torch_metrics(torch_metrics)

process the torch_metrics parameter.

cpu()

See torch.nn.Module.cpu().

cuda([device])

Moves all model parameters and buffers to the GPU.

double()

See torch.nn.Module.double().

eval()

Set the module in evaluation mode.

extra_repr()

Set the extra representation of the module.

float()

See torch.nn.Module.float().

forward(*args, **kwargs)

Same as torch.nn.Module.forward().

freeze()

Freeze all params for inference.

get_buffer(target)

Return the buffer given by target if it exists, otherwise throw an error.

get_extra_state()

Return any extra state to include in the module's state_dict.

get_parameter(target)

Return the parameter given by target if it exists, otherwise throw an error.

get_submodule(target)

Return the submodule given by target if it exists, otherwise throw an error.

half()

See torch.nn.Module.half().

ipu([device])

Move all model parameters and buffers to the IPU.

load_from_checkpoint(checkpoint_path[, ...])

Primary way of loading a model from a checkpoint.

load_state_dict(state_dict[, strict, assign])

Copy parameters and buffers from state_dict into this module and its descendants.

log(name, value[, prog_bar, logger, ...])

Log a key, value pair.

log_dict(dictionary[, prog_bar, logger, ...])

Log a dictionary of values at once.

lr_scheduler_step(scheduler, metric)

Override this method to adjust the default way the Trainer calls each scheduler.

lr_schedulers()

Returns the learning rate scheduler(s) that are being used during training.

manual_backward(loss, *args, **kwargs)

Call this directly from your training_step() when doing optimizations manually.

modules()

Return an iterator over all modules in the network.

named_buffers([prefix, recurse, ...])

Return an iterator over module buffers, yielding both the name of the buffer as well as the buffer itself.

named_children()

Return an iterator over immediate children modules, yielding both the name of the module as well as the module itself.

named_modules([memo, prefix, remove_duplicate])

Return an iterator over all modules in the network, yielding both the name of the module as well as the module itself.

named_parameters([prefix, recurse, ...])

Return an iterator over module parameters, yielding both the name of the parameter as well as the parameter itself.

on_after_backward()

Called after loss.backward() and before optimizers are stepped.

on_after_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch after it is transferred to the device.

on_before_backward(loss)

Called before loss.backward().

on_before_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch before it is transferred to the device.

on_before_optimizer_step(optimizer)

Called before optimizer.step().

on_before_zero_grad(optimizer)

Called after training_step() and before optimizer.zero_grad().

on_fit_end()

Called at the very end of fit.

on_fit_start()

Called at the very beginning of fit.

on_load_checkpoint(checkpoint)

Called by Lightning to restore your model.

on_predict_batch_end(outputs, batch, batch_idx)

Called in the predict loop after the batch.

on_predict_batch_start(batch, batch_idx[, ...])

Called in the predict loop before anything happens for that batch.

on_predict_end()

Called at the end of predicting.

on_predict_epoch_end()

Called at the end of predicting.

on_predict_epoch_start()

Called at the beginning of predicting.

on_predict_model_eval()

Called when the predict loop starts.

on_predict_start()

Called at the beginning of predicting.

on_save_checkpoint(checkpoint)

Called by Lightning when saving a checkpoint to give you a chance to store anything else you might want to save.

on_test_batch_end(outputs, batch, batch_idx)

Called in the test loop after the batch.

on_test_batch_start(batch, batch_idx[, ...])

Called in the test loop before anything happens for that batch.

on_test_end()

Called at the end of testing.

on_test_epoch_end()

Called in the test loop at the very end of the epoch.

on_test_epoch_start()

Called in the test loop at the very beginning of the epoch.

on_test_model_eval()

Called when the test loop starts.

on_test_model_train()

Called when the test loop ends.

on_test_start()

Called at the beginning of testing.

on_train_batch_end(outputs, batch, batch_idx)

Called in the training loop after the batch.

on_train_batch_start(batch, batch_idx)

Called in the training loop before anything happens for that batch.

on_train_end()

Called at the end of training before logger experiment is closed.

on_train_epoch_end()

Called in the training loop at the very end of the epoch.

on_train_epoch_start()

Called in the training loop at the very beginning of the epoch.

on_train_start()

Called at the beginning of training after sanity check.

on_validation_batch_end(outputs, batch, ...)

Called in the validation loop after the batch.

on_validation_batch_start(batch, batch_idx)

Called in the validation loop before anything happens for that batch.

on_validation_end()

Called at the end of validation.

on_validation_epoch_end()

Called in the validation loop at the very end of the epoch.

on_validation_epoch_start()

Called in the validation loop at the very beginning of the epoch.

on_validation_model_eval()

Called when the validation loop starts.

on_validation_model_train()

Called when the validation loop ends.

on_validation_model_zero_grad()

Called by the training loop to release gradients before entering the validation loop.

on_validation_start()

Called at the beginning of validation.

optimizer_step(epoch, batch_idx, optimizer)

Override this method to adjust the default way the Trainer calls the optimizer.

optimizer_zero_grad(epoch, batch_idx, optimizer)

Override this method to change the default behaviour of optimizer.zero_grad().

optimizers([use_pl_optimizer])

Returns the optimizer(s) that are being used during training.

parameters([recurse])

Return an iterator over module parameters.

predict_dataloader()

An iterable or collection of iterables specifying prediction samples.

predict_step(batch, batch_idx[, dataloader_idx])

performs the prediction step

prepare_data()

Use this to download and prepare data.

print(*args, **kwargs)

Prints only from process 0.

register_backward_hook(hook)

Register a backward hook on the module.

register_buffer(name, tensor[, persistent])

Add a buffer to the module.

register_forward_hook(hook, *[, prepend, ...])

Register a forward hook on the module.

register_forward_pre_hook(hook, *[, ...])

Register a forward pre-hook on the module.

register_full_backward_hook(hook[, prepend])

Register a backward hook on the module.

register_full_backward_pre_hook(hook[, prepend])

Register a backward pre-hook on the module.

register_load_state_dict_post_hook(hook)

Register a post hook to be run after module's load_state_dict is called.

register_module(name, module)

Alias for add_module().

register_parameter(name, param)

Add a parameter to the module.

register_state_dict_pre_hook(hook)

Register a pre-hook for the load_state_dict() method.

requires_grad_([requires_grad])

Change if autograd should record operations on parameters in this module.

save_hyperparameters(*args[, ignore, frame, ...])

Save arguments to hparams attribute.

set_extra_state(state)

Set extra state contained in the loaded state_dict.

set_predict_parameters(n, num_samples, ...)

to be set from TorchForecastingModel before calling trainer.predict() and reset at self.on_predict_end()

setup(stage)

Called at the beginning of fit (train + validate), validate, test, or predict.

share_memory()

See torch.Tensor.share_memory_().

state_dict(*args[, destination, prefix, ...])

Return a dictionary containing references to the whole state of the module.

teardown(stage)

Called at the end of fit (train + validate), validate, test, or predict.

test_dataloader()

An iterable or collection of iterables specifying test samples.

test_step(*args, **kwargs)

Operates on a single batch of data from the test set.

to(*args, **kwargs)

See torch.nn.Module.to().

to_dtype(dtype)

Cast module precision (float32 by default) to another precision.

to_empty(*, device[, recurse])

Move the parameters and buffers to the specified device without copying storage.

to_onnx(file_path[, input_sample])

Saves the model in ONNX format.

to_torchscript([file_path, method, ...])

By default compiles the whole model to a ScriptModule.

toggle_optimizer(optimizer)

Makes sure only the gradients of the current optimizer's parameters are calculated in the training step to prevent dangling gradients in multiple-optimizer setup.

train([mode])

Set the module in training mode.

train_dataloader()

An iterable or collection of iterables specifying training samples.

training_step(train_batch, batch_idx)

performs the training step

transfer_batch_to_device(batch, device, ...)

Override this hook if your DataLoader returns tensors wrapped in a custom data structure.

type(dst_type)

See torch.nn.Module.type().

unfreeze()

Unfreeze all parameters for training.

untoggle_optimizer(optimizer)

Resets the state of required gradients that were toggled with toggle_optimizer().

val_dataloader()

An iterable or collection of iterables specifying validation samples.

validation_step(val_batch, batch_idx)

performs the validation step

xpu([device])

Move all model parameters and buffers to the XPU.

zero_grad([set_to_none])

Reset gradients of all model parameters.

__call__

set_mc_dropout

CHECKPOINT_HYPER_PARAMS_KEY = 'hyper_parameters'
CHECKPOINT_HYPER_PARAMS_NAME = 'hparams_name'
CHECKPOINT_HYPER_PARAMS_TYPE = 'hparams_type'
T_destination

alias of TypeVar(‘T_destination’, bound=Dict[str, Any])

add_module(name, module)

Add a child module to the current module.

The module can be accessed as an attribute using the given name.

Parameters
  • name (str) – name of the child module. The child module can be accessed from this module using the given name

  • module (Module) – child module to be added to the module.

Return type

None

all_gather(data, group=None, sync_grads=False)

Gather tensors or collections of tensors from multiple processes.

This method needs to be called on all processes and the tensors need to have the same shape across all processes, otherwise your program will stall forever.

Parameters
  • data (Union[Tensor, Dict, List, Tuple]) – int, float, tensor of shape (batch, …), or a (possibly nested) collection thereof.

  • group (Optional[Any]) – the process group to gather results from. Defaults to all processes (world)

  • sync_grads (bool) – flag that allows users to synchronize gradients for the all_gather operation

Return type

Union[Tensor, Dict, List, Tuple]

Returns

A tensor of shape (world_size, batch, …), or if the input was a collection the output will also be a collection with tensors of this shape.

apply(fn)

Apply fn recursively to every submodule (as returned by .children()) as well as self.

Typical use includes initializing the parameters of a model (see also nn-init-doc).

Parameters

fn (Module -> None) – function to be applied to each submodule

Returns

self

Return type

Module

Example:

>>> @torch.no_grad()
>>> def init_weights(m):
>>>     print(m)
>>>     if type(m) == nn.Linear:
>>>         m.weight.fill_(1.0)
>>>         print(m.weight)
>>> net = nn.Sequential(nn.Linear(2, 2), nn.Linear(2, 2))
>>> net.apply(init_weights)
Linear(in_features=2, out_features=2, bias=True)
Parameter containing:
tensor([[1., 1.],
        [1., 1.]], requires_grad=True)
Linear(in_features=2, out_features=2, bias=True)
Parameter containing:
tensor([[1., 1.],
        [1., 1.]], requires_grad=True)
Sequential(
  (0): Linear(in_features=2, out_features=2, bias=True)
  (1): Linear(in_features=2, out_features=2, bias=True)
)
property automatic_optimization: bool

If set to False you are responsible for calling .backward(), .step(), .zero_grad().

Return type

bool

backward(loss, *args, **kwargs)

Called to perform backward on the loss returned in training_step(). Override this hook with your own implementation if you need to.

Parameters

loss (Tensor) – The loss tensor returned by training_step(). If gradient accumulation is used, the loss here holds the normalized value (scaled by 1 / accumulation steps).

Example:

def backward(self, loss):
    loss.backward()
Return type

None

bfloat16()

Casts all floating point parameters and buffers to bfloat16 datatype.

Note

This method modifies the module in-place.

Returns

self

Return type

Module

buffers(recurse=True)

Return an iterator over module buffers.

Parameters

recurse (bool) – if True, then yields buffers of this module and all submodules. Otherwise, yields only buffers that are direct members of this module.

Yields

torch.Tensor – module buffer

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for buf in model.buffers():
>>>     print(type(buf), buf.size())
<class 'torch.Tensor'> (20L,)
<class 'torch.Tensor'> (20L, 1L, 5L, 5L)
Return type

Iterator[Tensor]

call_super_init: bool = False
children()

Return an iterator over immediate children modules.

Yields

Module – a child module

Return type

Iterator[Module]

clip_gradients(optimizer, gradient_clip_val=None, gradient_clip_algorithm=None)

Handles gradient clipping internally.

Note

  • Do not override this method. If you want to customize gradient clipping, consider using configure_gradient_clipping() method.

  • For manual optimization (self.automatic_optimization = False), if you want to use gradient clipping, consider calling self.clip_gradients(opt, gradient_clip_val=0.5, gradient_clip_algorithm="norm") manually in the training step.

Parameters
  • optimizer (Optimizer) – Current optimizer being used.

  • gradient_clip_val (Union[int, float, None]) – The value at which to clip gradients.

  • gradient_clip_algorithm (Optional[str]) – The gradient clipping algorithm to use. Pass gradient_clip_algorithm="value" to clip by value, and gradient_clip_algorithm="norm" to clip by norm.

Return type

None

compile(*args, **kwargs)

Compile this Module’s forward using torch.compile().

This Module’s __call__ method is compiled and all arguments are passed as-is to torch.compile().

See torch.compile() for details on the arguments for this function.

configure_callbacks()

Configure model-specific callbacks. When the model gets attached, e.g., when .fit() or .test() gets called, the list or a callback returned here will be merged with the list of callbacks passed to the Trainer’s callbacks argument. If a callback returned here has the same type as one or several callbacks already present in the Trainer’s callbacks list, it will take priority and replace them. In addition, Lightning will make sure ModelCheckpoint callbacks run last.

Return type

Union[Sequence[Callback], Callback]

Returns

A callback or a list of callbacks which will extend the list of callbacks in the Trainer.

Example:

def configure_callbacks(self):
    early_stop = EarlyStopping(monitor="val_acc", mode="max")
    checkpoint = ModelCheckpoint(monitor="val_loss")
    return [early_stop, checkpoint]
configure_gradient_clipping(optimizer, gradient_clip_val=None, gradient_clip_algorithm=None)

Perform gradient clipping for the optimizer parameters. Called before optimizer_step().

Parameters
  • optimizer (Optimizer) – Current optimizer being used.

  • gradient_clip_val (Union[int, float, None]) – The value at which to clip gradients. By default, value passed in Trainer will be available here.

  • gradient_clip_algorithm (Optional[str]) – The gradient clipping algorithm to use. By default, value passed in Trainer will be available here.

Example:

def configure_gradient_clipping(self, optimizer, gradient_clip_val, gradient_clip_algorithm):
    # Implement your own custom logic to clip gradients
    # You can call `self.clip_gradients` with your settings:
    self.clip_gradients(
        optimizer,
        gradient_clip_val=gradient_clip_val,
        gradient_clip_algorithm=gradient_clip_algorithm
    )
Return type

None

configure_model()

Hook to create modules in a strategy and precision aware context.

This is particularly useful for when using sharded strategies (FSDP and DeepSpeed), where we’d like to shard the model instantly to save memory and initialization time. For non-sharded strategies, you can choose to override this hook or to initialize your model under the init_module() context manager.

This hook is called during each of fit/val/test/predict stages in the same process, so ensure that implementation of this hook is idempotent, i.e., after the first time the hook is called, subsequent calls to it should be a no-op.

Return type

None

configure_optimizers()[source]

configures optimizers and learning rate schedulers for model optimization.

configure_sharded_model()

Deprecated.

Use configure_model() instead.

Return type

None

static configure_torch_metrics(torch_metrics)[source]

process the torch_metrics parameter.

Return type

MetricCollection

cpu()

See torch.nn.Module.cpu().

Return type

Self

cuda(device=None)

Moves all model parameters and buffers to the GPU. This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on GPU while being optimized.

Parameters

device (Union[int, device, None]) – If specified, all parameters will be copied to that device. If None, the current CUDA device index will be used.

Returns

self

Return type

Module

property current_epoch: int

The current epoch in the Trainer, or 0 if not attached.

Return type

int

property device: device
Return type

device

double()

See torch.nn.Module.double().

Return type

Self

property dtype: Union[str, dtype]
Return type

Union[str, dtype]

dump_patches: bool = False
property epochs_trained
eval()

Set the module in evaluation mode.

This has any effect only on certain modules. See documentations of particular modules for details of their behaviors in training/evaluation mode, if they are affected, e.g. Dropout, BatchNorm, etc.

This is equivalent with self.train(False).

See locally-disable-grad-doc for a comparison between .eval() and several similar mechanisms that may be confused with it.

Returns

self

Return type

Module

property example_input_array: Optional[Union[Tensor, Tuple, Dict]]

The example input array is a specification of what the module can consume in the forward() method. The return type is interpreted as follows:

  • Single tensor: It is assumed the model takes a single argument, i.e., model.forward(model.example_input_array)

  • Tuple: The input array should be interpreted as a sequence of positional arguments, i.e., model.forward(*model.example_input_array)

  • Dict: The input array represents named keyword arguments, i.e., model.forward(**model.example_input_array)

Return type

Union[Tensor, Tuple, Dict, None]

extra_repr()

Set the extra representation of the module.

To print customized extra information, you should re-implement this method in your own modules. Both single-line and multi-line strings are acceptable.

Return type

str

property fabric: Optional[Fabric]
Return type

Optional[Fabric]

float()

See torch.nn.Module.float().

Return type

Self

abstract forward(*args, **kwargs)[source]

Same as torch.nn.Module.forward().

Parameters
  • *args – Whatever you decide to pass into the forward method.

  • **kwargs – Keyword arguments are also possible.

Return type

Any

Returns

Your model’s output

freeze()

Freeze all params for inference.

Example:

model = MyLightningModule(...)
model.freeze()
Return type

None

get_buffer(target)

Return the buffer given by target if it exists, otherwise throw an error.

See the docstring for get_submodule for a more detailed explanation of this method’s functionality as well as how to correctly specify target.

Parameters

target (str) – The fully-qualified string name of the buffer to look for. (See get_submodule for how to specify a fully-qualified string.)

Returns

The buffer referenced by target

Return type

torch.Tensor

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not a buffer

get_extra_state()

Return any extra state to include in the module’s state_dict.

Implement this and a corresponding set_extra_state() for your module if you need to store extra state. This function is called when building the module’s state_dict().

Note that extra state should be picklable to ensure working serialization of the state_dict. We only provide provide backwards compatibility guarantees for serializing Tensors; other objects may break backwards compatibility if their serialized pickled form changes.

Returns

Any extra state to store in the module’s state_dict

Return type

object

get_parameter(target)

Return the parameter given by target if it exists, otherwise throw an error.

See the docstring for get_submodule for a more detailed explanation of this method’s functionality as well as how to correctly specify target.

Parameters

target (str) – The fully-qualified string name of the Parameter to look for. (See get_submodule for how to specify a fully-qualified string.)

Returns

The Parameter referenced by target

Return type

torch.nn.Parameter

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not an nn.Parameter

get_submodule(target)

Return the submodule given by target if it exists, otherwise throw an error.

For example, let’s say you have an nn.Module A that looks like this:

A(
    (net_b): Module(
        (net_c): Module(
            (conv): Conv2d(16, 33, kernel_size=(3, 3), stride=(2, 2))
        )
        (linear): Linear(in_features=100, out_features=200, bias=True)
    )
)

(The diagram shows an nn.Module A. A has a nested submodule net_b, which itself has two submodules net_c and linear. net_c then has a submodule conv.)

To check whether or not we have the linear submodule, we would call get_submodule("net_b.linear"). To check whether we have the conv submodule, we would call get_submodule("net_b.net_c.conv").

The runtime of get_submodule is bounded by the degree of module nesting in target. A query against named_modules achieves the same result, but it is O(N) in the number of transitive modules. So, for a simple check to see if some submodule exists, get_submodule should always be used.

Parameters

target (str) – The fully-qualified string name of the submodule to look for. (See above example for how to specify a fully-qualified string.)

Returns

The submodule referenced by target

Return type

torch.nn.Module

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not an nn.Module

property global_rank: int

The index of the current process across all nodes and devices.

Return type

int

property global_step: int

Total training batches seen across all epochs.

If no Trainer is attached, this propery is 0.

Return type

int

half()

See torch.nn.Module.half().

Return type

Self

property hparams: Union[AttributeDict, MutableMapping]

The collection of hyperparameters saved with save_hyperparameters(). It is mutable by the user. For the frozen set of initial hyperparameters, use hparams_initial.

Return type

Union[AttributeDict, MutableMapping]

Returns

Mutable hyperparameters dictionary

property hparams_initial: AttributeDict

The collection of hyperparameters saved with save_hyperparameters(). These contents are read-only. Manual updates to the saved hyperparameters can instead be performed through hparams.

Returns

immutable initial hyperparameters

Return type

AttributeDict

ipu(device=None)

Move all model parameters and buffers to the IPU.

This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on IPU while being optimized.

Note

This method modifies the module in-place.

Parameters

device (int, optional) – if specified, all parameters will be copied to that device

Returns

self

Return type

Module

load_from_checkpoint(checkpoint_path, map_location=None, hparams_file=None, strict=None, **kwargs)

Primary way of loading a model from a checkpoint. When Lightning saves a checkpoint it stores the arguments passed to __init__ in the checkpoint under "hyper_parameters".

Any arguments specified through **kwargs will override args stored in "hyper_parameters".

Parameters
  • checkpoint_path (Union[str, Path, IO]) – Path to checkpoint. This can also be a URL, or file-like object

  • map_location (Union[device, str, int, Callable[[UntypedStorage, str], Optional[UntypedStorage]], Dict[Union[device, str, int], Union[device, str, int]], None]) – If your checkpoint saved a GPU model and you now load on CPUs or a different number of GPUs, use this to map to the new setup. The behaviour is the same as in torch.load().

  • hparams_file (Union[str, Path, None]) –

    Optional path to a .yaml or .csv file with hierarchical structure as in this example:

    drop_prob: 0.2
    dataloader:
        batch_size: 32
    

    You most likely won’t need this since Lightning will always save the hyperparameters to the checkpoint. However, if your checkpoint weights don’t have the hyperparameters saved, use this method to pass in a .yaml file with the hparams you’d like to use. These will be converted into a dict and passed into your LightningModule for use.

    If your model’s hparams argument is Namespace and .yaml file has hierarchical structure, you need to refactor your model to treat hparams as dict.

  • strict (Optional[bool]) – Whether to strictly enforce that the keys in checkpoint_path match the keys returned by this module’s state dict. Defaults to True unless LightningModule.strict_loading is set, in which case it defaults to the value of LightningModule.strict_loading.

  • **kwargs – Any extra keyword args needed to init the model. Can also be used to override saved hyperparameter values.

Return type

Self

Returns

LightningModule instance with loaded weights and hyperparameters (if available).

Note

load_from_checkpoint is a class method. You should use your LightningModule class to call it instead of the LightningModule instance, or a TypeError will be raised.

Note

To ensure all layers can be loaded from the checkpoint, this function will call configure_model() directly after instantiating the model if this hook is overridden in your LightningModule. However, note that load_from_checkpoint does not support loading sharded checkpoints, and you may run out of memory if the model is too large. In this case, consider loading through the Trainer via .fit(ckpt_path=...).

Example:

# load weights without mapping ...
model = MyLightningModule.load_from_checkpoint('path/to/checkpoint.ckpt')

# or load weights mapping all weights from GPU 1 to GPU 0 ...
map_location = {'cuda:1':'cuda:0'}
model = MyLightningModule.load_from_checkpoint(
    'path/to/checkpoint.ckpt',
    map_location=map_location
)

# or load weights and hyperparameters from separate files.
model = MyLightningModule.load_from_checkpoint(
    'path/to/checkpoint.ckpt',
    hparams_file='/path/to/hparams_file.yaml'
)

# override some of the params with new values
model = MyLightningModule.load_from_checkpoint(
    PATH,
    num_layers=128,
    pretrained_ckpt_path=NEW_PATH,
)

# predict
pretrained_model.eval()
pretrained_model.freeze()
y_hat = pretrained_model(x)
load_state_dict(state_dict, strict=True, assign=False)

Copy parameters and buffers from state_dict into this module and its descendants.

If strict is True, then the keys of state_dict must exactly match the keys returned by this module’s state_dict() function.

Warning

If assign is True the optimizer must be created after the call to load_state_dict.

Parameters
  • state_dict (dict) – a dict containing parameters and persistent buffers.

  • strict (bool, optional) – whether to strictly enforce that the keys in state_dict match the keys returned by this module’s state_dict() function. Default: True

  • assign (bool, optional) – whether to assign items in the state dictionary to their corresponding keys in the module instead of copying them inplace into the module’s current parameters and buffers. When False, the properties of the tensors in the current module are preserved while when True, the properties of the Tensors in the state dict are preserved. Default: False

Returns

  • missing_keys is a list of str containing the missing keys

  • unexpected_keys is a list of str containing the unexpected keys

Return type

NamedTuple with missing_keys and unexpected_keys fields

Note

If a parameter or buffer is registered as None and its corresponding key exists in state_dict, load_state_dict() will raise a RuntimeError.

property local_rank: int

The index of the current process within a single node.

Return type

int

log(name, value, prog_bar=False, logger=None, on_step=None, on_epoch=None, reduce_fx='mean', enable_graph=False, sync_dist=False, sync_dist_group=None, add_dataloader_idx=True, batch_size=None, metric_attribute=None, rank_zero_only=False)

Log a key, value pair.

Example:

self.log('train_loss', loss)

The default behavior per hook is documented here: extensions/logging:Automatic Logging.

Parameters
  • name (str) – key to log.

  • value (Union[Metric, Tensor, int, float]) – value to log. Can be a float, Tensor, or a Metric.

  • prog_bar (bool) – if True logs to the progress bar.

  • logger (Optional[bool]) – if True logs to the logger.

  • on_step (Optional[bool]) – if True logs at this step. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • on_epoch (Optional[bool]) – if True logs epoch accumulated metrics. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • reduce_fx (Union[str, Callable]) – reduction function over step values for end of epoch. torch.mean() by default.

  • enable_graph (bool) – if True, will not auto detach the graph.

  • sync_dist (bool) – if True, reduces the metric across devices. Use with care as this may lead to a significant communication overhead.

  • sync_dist_group (Optional[Any]) – the DDP group to sync across.

  • add_dataloader_idx (bool) – if True, appends the index of the current dataloader to the name (when using multiple dataloaders). If False, user needs to give unique names for each dataloader to not mix the values.

  • batch_size (Optional[int]) – Current batch_size. This will be directly inferred from the loaded batch, but for some data structures you might need to explicitly provide it.

  • metric_attribute (Optional[str]) – To restore the metric state, Lightning requires the reference of the torchmetrics.Metric in your model. This is found automatically if it is a model attribute.

  • rank_zero_only (bool) – Tells Lightning if you are calling self.log from every process (default) or only from rank 0. If True, you won’t be able to use this metric as a monitor in callbacks (e.g., early stopping). Warning: Improper use can lead to deadlocks! See Advanced Logging for more details.

Return type

None

log_dict(dictionary, prog_bar=False, logger=None, on_step=None, on_epoch=None, reduce_fx='mean', enable_graph=False, sync_dist=False, sync_dist_group=None, add_dataloader_idx=True, batch_size=None, rank_zero_only=False)

Log a dictionary of values at once.

Example:

values = {'loss': loss, 'acc': acc, ..., 'metric_n': metric_n}
self.log_dict(values)
Parameters
  • dictionary (Union[Mapping[str, Union[Metric, Tensor, int, float]], MetricCollection]) – key value pairs. The values can be a float, Tensor, Metric, or MetricCollection.

  • prog_bar (bool) – if True logs to the progress base.

  • logger (Optional[bool]) – if True logs to the logger.

  • on_step (Optional[bool]) – if True logs at this step. None auto-logs for training_step but not validation/test_step. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • on_epoch (Optional[bool]) – if True logs epoch accumulated metrics. None auto-logs for val/test step but not training_step. The default value is determined by the hook. See extensions/logging:Automatic Logging for details.

  • reduce_fx (Union[str, Callable]) – reduction function over step values for end of epoch. torch.mean() by default.

  • enable_graph (bool) – if True, will not auto-detach the graph

  • sync_dist (bool) – if True, reduces the metric across GPUs/TPUs. Use with care as this may lead to a significant communication overhead.

  • sync_dist_group (Optional[Any]) – the ddp group to sync across.

  • add_dataloader_idx (bool) – if True, appends the index of the current dataloader to the name (when using multiple). If False, user needs to give unique names for each dataloader to not mix values.

  • batch_size (Optional[int]) – Current batch size. This will be directly inferred from the loaded batch, but some data structures might need to explicitly provide it.

  • rank_zero_only (bool) – Tells Lightning if you are calling self.log from every process (default) or only from rank 0. If True, you won’t be able to use this metric as a monitor in callbacks (e.g., early stopping). Warning: Improper use can lead to deadlocks! See Advanced Logging for more details.

Return type

None

property logger: Optional[Union[Logger, Logger]]

Reference to the logger object in the Trainer.

Return type

Union[Logger, Logger, None]

property loggers: Union[List[Logger], List[Logger]]

Reference to the list of loggers in the Trainer.

Return type

Union[List[Logger], List[Logger]]

lr_scheduler_step(scheduler, metric)

Override this method to adjust the default way the Trainer calls each scheduler. By default, Lightning calls step() and as shown in the example for each scheduler based on its interval.

Parameters
  • scheduler (Union[LRScheduler, ReduceLROnPlateau]) – Learning rate scheduler.

  • metric (Optional[Any]) – Value of the monitor used for schedulers like ReduceLROnPlateau.

Examples:

# DEFAULT
def lr_scheduler_step(self, scheduler, metric):
    if metric is None:
        scheduler.step()
    else:
        scheduler.step(metric)

# Alternative way to update schedulers if it requires an epoch value
def lr_scheduler_step(self, scheduler, metric):
    scheduler.step(epoch=self.current_epoch)
Return type

None

lr_schedulers()

Returns the learning rate scheduler(s) that are being used during training. Useful for manual optimization.

Return type

Union[None, List[Union[LRScheduler, ReduceLROnPlateau]], LRScheduler, ReduceLROnPlateau]

Returns

A single scheduler, or a list of schedulers in case multiple ones are present, or None if no schedulers were returned in configure_optimizers().

manual_backward(loss, *args, **kwargs)

Call this directly from your training_step() when doing optimizations manually. By using this, Lightning can ensure that all the proper scaling gets applied when using mixed precision.

See manual optimization for more examples.

Example:

def training_step(...):
    opt = self.optimizers()
    loss = ...
    opt.zero_grad()
    # automatically applies scaling, etc...
    self.manual_backward(loss)
    opt.step()
Parameters
  • loss (Tensor) – The tensor on which to compute gradients. Must have a graph attached.

  • *args – Additional positional arguments to be forwarded to backward()

  • **kwargs – Additional keyword arguments to be forwarded to backward()

Return type

None

modules()

Return an iterator over all modules in the network.

Yields

Module – a module in the network

Note

Duplicate modules are returned only once. In the following example, l will be returned only once.

Example:

>>> l = nn.Linear(2, 2)
>>> net = nn.Sequential(l, l)
>>> for idx, m in enumerate(net.modules()):
...     print(idx, '->', m)

0 -> Sequential(
  (0): Linear(in_features=2, out_features=2, bias=True)
  (1): Linear(in_features=2, out_features=2, bias=True)
)
1 -> Linear(in_features=2, out_features=2, bias=True)
Return type

Iterator[Module]

named_buffers(prefix='', recurse=True, remove_duplicate=True)

Return an iterator over module buffers, yielding both the name of the buffer as well as the buffer itself.

Parameters
  • prefix (str) – prefix to prepend to all buffer names.

  • recurse (bool, optional) – if True, then yields buffers of this module and all submodules. Otherwise, yields only buffers that are direct members of this module. Defaults to True.

  • remove_duplicate (bool, optional) – whether to remove the duplicated buffers in the result. Defaults to True.

Yields

(str, torch.Tensor) – Tuple containing the name and buffer

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for name, buf in self.named_buffers():
>>>     if name in ['running_var']:
>>>         print(buf.size())
Return type

Iterator[Tuple[str, Tensor]]

named_children()

Return an iterator over immediate children modules, yielding both the name of the module as well as the module itself.

Yields

(str, Module) – Tuple containing a name and child module

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for name, module in model.named_children():
>>>     if name in ['conv4', 'conv5']:
>>>         print(module)
Return type

Iterator[Tuple[str, Module]]

named_modules(memo=None, prefix='', remove_duplicate=True)

Return an iterator over all modules in the network, yielding both the name of the module as well as the module itself.

Parameters
  • memo (Optional[Set[Module]]) – a memo to store the set of modules already added to the result

  • prefix (str) – a prefix that will be added to the name of the module

  • remove_duplicate (bool) – whether to remove the duplicated module instances in the result or not

Yields

(str, Module) – Tuple of name and module

Note

Duplicate modules are returned only once. In the following example, l will be returned only once.

Example:

>>> l = nn.Linear(2, 2)
>>> net = nn.Sequential(l, l)
>>> for idx, m in enumerate(net.named_modules()):
...     print(idx, '->', m)

0 -> ('', Sequential(
  (0): Linear(in_features=2, out_features=2, bias=True)
  (1): Linear(in_features=2, out_features=2, bias=True)
))
1 -> ('0', Linear(in_features=2, out_features=2, bias=True))
named_parameters(prefix='', recurse=True, remove_duplicate=True)

Return an iterator over module parameters, yielding both the name of the parameter as well as the parameter itself.

Parameters
  • prefix (str) – prefix to prepend to all parameter names.

  • recurse (bool) – if True, then yields parameters of this module and all submodules. Otherwise, yields only parameters that are direct members of this module.

  • remove_duplicate (bool, optional) – whether to remove the duplicated parameters in the result. Defaults to True.

Yields

(str, Parameter) – Tuple containing the name and parameter

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for name, param in self.named_parameters():
>>>     if name in ['bias']:
>>>         print(param.size())
Return type

Iterator[Tuple[str, Parameter]]

on_after_backward()

Called after loss.backward() and before optimizers are stepped.

Note

If using native AMP, the gradients will not be unscaled at this point. Use the on_before_optimizer_step if you need the unscaled gradients.

Return type

None

on_after_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch after it is transferred to the device.

Note

To check the current state of execution of this hook you can use self.trainer.training/testing/validating/predicting so that you can add different logic as per your requirement.

Parameters
  • batch (Any) – A batch of data that needs to be altered or augmented.

  • dataloader_idx (int) – The index of the dataloader to which the batch belongs.

Return type

Any

Returns

A batch of data

Example:

def on_after_batch_transfer(self, batch, dataloader_idx):
    batch['x'] = gpu_transforms(batch['x'])
    return batch
Raises

MisconfigurationException – If using IPUs, Trainer(accelerator='ipu').

on_before_backward(loss)

Called before loss.backward().

Parameters

loss (Tensor) – Loss divided by number of batches for gradient accumulation and scaled if using AMP.

Return type

None

on_before_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch before it is transferred to the device.

Note

To check the current state of execution of this hook you can use self.trainer.training/testing/validating/predicting so that you can add different logic as per your requirement.

Parameters
  • batch (Any) – A batch of data that needs to be altered or augmented.

  • dataloader_idx (int) – The index of the dataloader to which the batch belongs.

Return type

Any

Returns

A batch of data

Example:

def on_before_batch_transfer(self, batch, dataloader_idx):
    batch['x'] = transforms(batch['x'])
    return batch
on_before_optimizer_step(optimizer)

Called before optimizer.step().

If using gradient accumulation, the hook is called once the gradients have been accumulated. See: :paramref:`~pytorch_lightning.trainer.trainer.Trainer.accumulate_grad_batches`.

If using AMP, the loss will be unscaled before calling this hook. See these docs for more information on the scaling of gradients.

If clipping gradients, the gradients will not have been clipped yet.

Parameters

optimizer (Optimizer) – Current optimizer being used.

Example:

def on_before_optimizer_step(self, optimizer):
    # example to inspect gradient information in tensorboard
    if self.trainer.global_step % 25 == 0:  # don't make the tf file huge
        for k, v in self.named_parameters():
            self.logger.experiment.add_histogram(
                tag=k, values=v.grad, global_step=self.trainer.global_step
            )
Return type

None

on_before_zero_grad(optimizer)

Called after training_step() and before optimizer.zero_grad().

Called in the training loop after taking an optimizer step and before zeroing grads. Good place to inspect weight information with weights updated.

This is where it is called:

for optimizer in optimizers:
    out = training_step(...)

    model.on_before_zero_grad(optimizer) # < ---- called here
    optimizer.zero_grad()

    backward()
Parameters

optimizer (Optimizer) – The optimizer for which grads should be zeroed.

Return type

None

on_fit_end()

Called at the very end of fit.

If on DDP it is called on every process

Return type

None

on_fit_start()

Called at the very beginning of fit.

If on DDP it is called on every process

Return type

None

property on_gpu: bool

Returns True if this model is currently located on a GPU.

Useful to set flags around the LightningModule for different CPU vs GPU behavior.

Return type

bool

on_load_checkpoint(checkpoint)[source]

Called by Lightning to restore your model. If you saved something with on_save_checkpoint() this is your chance to restore this.

Parameters

checkpoint (Dict[str, Any]) – Loaded checkpoint

Example:

def on_load_checkpoint(self, checkpoint):
    # 99% of the time you don't need to implement this method
    self.something_cool_i_want_to_save = checkpoint['something_cool_i_want_to_save']

Note

Lightning auto-restores global step, epoch, and train state including amp scaling. There is no need for you to restore anything regarding training.

Return type

None

on_predict_batch_end(outputs, batch, batch_idx, dataloader_idx=0)

Called in the predict loop after the batch.

Parameters
  • outputs (Optional[Any]) – The outputs of predict_step(x)

  • batch (Any) – The batched data as it is returned by the prediction DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_predict_batch_start(batch, batch_idx, dataloader_idx=0)

Called in the predict loop before anything happens for that batch.

Parameters
  • batch (Any) – The batched data as it is returned by the test DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_predict_end()[source]

Called at the end of predicting.

Return type

None

on_predict_epoch_end()

Called at the end of predicting.

Return type

None

on_predict_epoch_start()

Called at the beginning of predicting.

Return type

None

on_predict_model_eval()

Called when the predict loop starts.

The predict loop by default calls .eval() on the LightningModule before it starts. Override this hook to change the behavior.

Return type

None

on_predict_start()[source]

Called at the beginning of predicting.

Return type

None

on_save_checkpoint(checkpoint)[source]

Called by Lightning when saving a checkpoint to give you a chance to store anything else you might want to save.

Parameters

checkpoint (Dict[str, Any]) – The full checkpoint dictionary before it gets dumped to a file. Implementations of this hook can insert additional data into this dictionary.

Example:

def on_save_checkpoint(self, checkpoint):
    # 99% of use cases you don't need to implement this method
    checkpoint['something_cool_i_want_to_save'] = my_cool_pickable_object

Note

Lightning saves all aspects of training (epoch, global step, etc…) including amp scaling. There is no need for you to store anything about training.

Return type

None

on_test_batch_end(outputs, batch, batch_idx, dataloader_idx=0)

Called in the test loop after the batch.

Parameters
  • outputs (Union[Tensor, Mapping[str, Any], None]) – The outputs of test_step(x)

  • batch (Any) – The batched data as it is returned by the test DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_test_batch_start(batch, batch_idx, dataloader_idx=0)

Called in the test loop before anything happens for that batch.

Parameters
  • batch (Any) – The batched data as it is returned by the test DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_test_end()

Called at the end of testing.

Return type

None

on_test_epoch_end()

Called in the test loop at the very end of the epoch.

Return type

None

on_test_epoch_start()

Called in the test loop at the very beginning of the epoch.

Return type

None

on_test_model_eval()

Called when the test loop starts.

The test loop by default calls .eval() on the LightningModule before it starts. Override this hook to change the behavior. See also on_test_model_train().

Return type

None

on_test_model_train()

Called when the test loop ends.

The test loop by default restores the training mode of the LightningModule to what it was before starting testing. Override this hook to change the behavior. See also on_test_model_eval().

Return type

None

on_test_start()

Called at the beginning of testing.

Return type

None

on_train_batch_end(outputs, batch, batch_idx)

Called in the training loop after the batch.

Parameters
  • outputs (Union[Tensor, Mapping[str, Any], None]) – The outputs of training_step(x)

  • batch (Any) – The batched data as it is returned by the training DataLoader.

  • batch_idx (int) – the index of the batch

Return type

None

on_train_batch_start(batch, batch_idx)

Called in the training loop before anything happens for that batch.

If you return -1 here, you will skip training for the rest of the current epoch.

Parameters
  • batch (Any) – The batched data as it is returned by the training DataLoader.

  • batch_idx (int) – the index of the batch

Return type

Optional[int]

on_train_end()

Called at the end of training before logger experiment is closed.

Return type

None

on_train_epoch_end()

Called in the training loop at the very end of the epoch.

To access all batch outputs at the end of the epoch, you can cache step outputs as an attribute of the LightningModule and access them in this hook:

class MyLightningModule(L.LightningModule):
    def __init__(self):
        super().__init__()
        self.training_step_outputs = []

    def training_step(self):
        loss = ...
        self.training_step_outputs.append(loss)
        return loss

    def on_train_epoch_end(self):
        # do something with all training_step outputs, for example:
        epoch_mean = torch.stack(self.training_step_outputs).mean()
        self.log("training_epoch_mean", epoch_mean)
        # free up the memory
        self.training_step_outputs.clear()
Return type

None

on_train_epoch_start()

Called in the training loop at the very beginning of the epoch.

Return type

None

on_train_start()

Called at the beginning of training after sanity check.

Return type

None

on_validation_batch_end(outputs, batch, batch_idx, dataloader_idx=0)

Called in the validation loop after the batch.

Parameters
  • outputs (Union[Tensor, Mapping[str, Any], None]) – The outputs of validation_step(x)

  • batch (Any) – The batched data as it is returned by the validation DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_validation_batch_start(batch, batch_idx, dataloader_idx=0)

Called in the validation loop before anything happens for that batch.

Parameters
  • batch (Any) – The batched data as it is returned by the validation DataLoader.

  • batch_idx (int) – the index of the batch

  • dataloader_idx (int) – the index of the dataloader

Return type

None

on_validation_end()

Called at the end of validation.

Return type

None

on_validation_epoch_end()

Called in the validation loop at the very end of the epoch.

Return type

None

on_validation_epoch_start()

Called in the validation loop at the very beginning of the epoch.

Return type

None

on_validation_model_eval()

Called when the validation loop starts.

The validation loop by default calls .eval() on the LightningModule before it starts. Override this hook to change the behavior. See also on_validation_model_train().

Return type

None

on_validation_model_train()

Called when the validation loop ends.

The validation loop by default restores the training mode of the LightningModule to what it was before starting validation. Override this hook to change the behavior. See also on_validation_model_eval().

Return type

None

on_validation_model_zero_grad()

Called by the training loop to release gradients before entering the validation loop.

Return type

None

on_validation_start()

Called at the beginning of validation.

Return type

None

optimizer_step(epoch, batch_idx, optimizer, optimizer_closure=None)

Override this method to adjust the default way the Trainer calls the optimizer.

By default, Lightning calls step() and zero_grad() as shown in the example. This method (and zero_grad()) won’t be called during the accumulation phase when Trainer(accumulate_grad_batches != 1). Overriding this hook has no benefit with manual optimization.

Parameters
  • epoch (int) – Current epoch

  • batch_idx (int) – Index of current batch

  • optimizer (Union[Optimizer, LightningOptimizer]) – A PyTorch optimizer

  • optimizer_closure (Optional[Callable[[], Any]]) – The optimizer closure. This closure must be executed as it includes the calls to training_step(), optimizer.zero_grad(), and backward().

Examples:

# DEFAULT
def optimizer_step(self, epoch, batch_idx, optimizer, optimizer_closure):
    optimizer.step(closure=optimizer_closure)

# Learning rate warm-up
def optimizer_step(self, epoch, batch_idx, optimizer, optimizer_closure):
    # update params
    optimizer.step(closure=optimizer_closure)

    # manually warm up lr without a scheduler
    if self.trainer.global_step < 500:
        lr_scale = min(1.0, float(self.trainer.global_step + 1) / 500.0)
        for pg in optimizer.param_groups:
            pg["lr"] = lr_scale * self.learning_rate
Return type

None

optimizer_zero_grad(epoch, batch_idx, optimizer)

Override this method to change the default behaviour of optimizer.zero_grad().

Parameters
  • epoch (int) – Current epoch

  • batch_idx (int) – Index of current batch

  • optimizer (Optimizer) – A PyTorch optimizer

Examples:

# DEFAULT
def optimizer_zero_grad(self, epoch, batch_idx, optimizer):
    optimizer.zero_grad()

# Set gradients to `None` instead of zero to improve performance (not required on `torch>=2.0.0`).
def optimizer_zero_grad(self, epoch, batch_idx, optimizer):
    optimizer.zero_grad(set_to_none=True)

See torch.optim.Optimizer.zero_grad() for the explanation of the above example.

Return type

None

optimizers(use_pl_optimizer=True)

Returns the optimizer(s) that are being used during training. Useful for manual optimization.

Parameters

use_pl_optimizer (bool) – If True, will wrap the optimizer(s) in a LightningOptimizer for automatic handling of precision, profiling, and counting of step calls for proper logging and checkpointing. It specifically wraps the step method and custom optimizers that don’t have this method are not supported.

Return type

Union[Optimizer, LightningOptimizer, _FabricOptimizer, List[Optimizer], List[LightningOptimizer], List[_FabricOptimizer]]

Returns

A single optimizer, or a list of optimizers in case multiple ones are present.

property output_chunk_length: Optional[int]

Number of time steps predicted at once by the model.

Return type

Optional[int]

parameters(recurse=True)

Return an iterator over module parameters.

This is typically passed to an optimizer.

Parameters

recurse (bool) – if True, then yields parameters of this module and all submodules. Otherwise, yields only parameters that are direct members of this module.

Yields

Parameter – module parameter

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for param in model.parameters():
>>>     print(type(param), param.size())
<class 'torch.Tensor'> (20L,)
<class 'torch.Tensor'> (20L, 1L, 5L, 5L)
Return type

Iterator[Parameter]

predict_dataloader()

An iterable or collection of iterables specifying prediction samples.

For more information about multiple dataloaders, see this section.

It’s recommended that all data downloads and preparation happen in prepare_data().

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware There is no need to set it yourself.

Return type

Any

Returns

A torch.utils.data.DataLoader or a sequence of them specifying prediction samples.

predict_step(batch, batch_idx, dataloader_idx=None)[source]

performs the prediction step

batch

output of Darts’ InferenceDataset - tuple of (past_target, past_covariates, historic_future_covariates, future_covariates, future_past_covariates, input time series, prediction start time step)

batch_idx

the batch index of the current batch

dataloader_idx

the dataloader index

Return type

Sequence[TimeSeries]

prepare_data()

Use this to download and prepare data. Downloading and saving data with multiple processes (distributed settings) will result in corrupted data. Lightning ensures this method is called only within a single process, so you can safely add your downloading logic within.

Warning

DO NOT set state to the model (use setup instead) since this is NOT called on every device

Example:

def prepare_data(self):
    # good
    download_data()
    tokenize()
    etc()

    # bad
    self.split = data_split
    self.some_state = some_other_state()

In a distributed environment, prepare_data can be called in two ways (using prepare_data_per_node)

  1. Once per node. This is the default and is only called on LOCAL_RANK=0.

  2. Once in total. Only called on GLOBAL_RANK=0.

Example:

# DEFAULT
# called once per node on LOCAL_RANK=0 of that node
class LitDataModule(LightningDataModule):
    def __init__(self):
        super().__init__()
        self.prepare_data_per_node = True

# call on GLOBAL_RANK=0 (great for shared file systems)
class LitDataModule(LightningDataModule):
    def __init__(self):
        super().__init__()
        self.prepare_data_per_node = False

This is called before requesting the dataloaders:

model.prepare_data()
initialize_distributed()
model.setup(stage)
model.train_dataloader()
model.val_dataloader()
model.test_dataloader()
model.predict_dataloader()
Return type

None

print(*args, **kwargs)

Prints only from process 0. Use this in any distributed mode to log only once.

Parameters
  • *args – The thing to print. The same as for Python’s built-in print function.

  • **kwargs – The same as for Python’s built-in print function.

Example:

def forward(self, x):
    self.print(x, 'in forward')
Return type

None

register_backward_hook(hook)

Register a backward hook on the module.

This function is deprecated in favor of register_full_backward_hook() and the behavior of this function will change in future versions.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_buffer(name, tensor, persistent=True)

Add a buffer to the module.

This is typically used to register a buffer that should not to be considered a model parameter. For example, BatchNorm’s running_mean is not a parameter, but is part of the module’s state. Buffers, by default, are persistent and will be saved alongside parameters. This behavior can be changed by setting persistent to False. The only difference between a persistent buffer and a non-persistent buffer is that the latter will not be a part of this module’s state_dict.

Buffers can be accessed as attributes using given names.

Parameters
  • name (str) – name of the buffer. The buffer can be accessed from this module using the given name

  • tensor (Tensor or None) – buffer to be registered. If None, then operations that run on buffers, such as cuda, are ignored. If None, the buffer is not included in the module’s state_dict.

  • persistent (bool) – whether the buffer is part of this module’s state_dict.

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> self.register_buffer('running_mean', torch.zeros(num_features))
Return type

None

register_forward_hook(hook, *, prepend=False, with_kwargs=False, always_call=False)

Register a forward hook on the module.

The hook will be called every time after forward() has computed an output.

If with_kwargs is False or not specified, the input contains only the positional arguments given to the module. Keyword arguments won’t be passed to the hooks and only to the forward. The hook can modify the output. It can modify the input inplace but it will not have effect on forward since this is called after forward() is called. The hook should have the following signature:

hook(module, args, output) -> None or modified output

If with_kwargs is True, the forward hook will be passed the kwargs given to the forward function and be expected to return the output possibly modified. The hook should have the following signature:

hook(module, args, kwargs, output) -> None or modified output
Parameters
  • hook (Callable) – The user defined hook to be registered.

  • prepend (bool) – If True, the provided hook will be fired before all existing forward hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing forward hooks on this torch.nn.modules.Module. Note that global forward hooks registered with register_module_forward_hook() will fire before all hooks registered by this method. Default: False

  • with_kwargs (bool) – If True, the hook will be passed the kwargs given to the forward function. Default: False

  • always_call (bool) – If True the hook will be run regardless of whether an exception is raised while calling the Module. Default: False

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_forward_pre_hook(hook, *, prepend=False, with_kwargs=False)

Register a forward pre-hook on the module.

The hook will be called every time before forward() is invoked.

If with_kwargs is false or not specified, the input contains only the positional arguments given to the module. Keyword arguments won’t be passed to the hooks and only to the forward. The hook can modify the input. User can either return a tuple or a single modified value in the hook. We will wrap the value into a tuple if a single value is returned (unless that value is already a tuple). The hook should have the following signature:

hook(module, args) -> None or modified input

If with_kwargs is true, the forward pre-hook will be passed the kwargs given to the forward function. And if the hook modifies the input, both the args and kwargs should be returned. The hook should have the following signature:

hook(module, args, kwargs) -> None or a tuple of modified input and kwargs
Parameters
  • hook (Callable) – The user defined hook to be registered.

  • prepend (bool) – If true, the provided hook will be fired before all existing forward_pre hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing forward_pre hooks on this torch.nn.modules.Module. Note that global forward_pre hooks registered with register_module_forward_pre_hook() will fire before all hooks registered by this method. Default: False

  • with_kwargs (bool) – If true, the hook will be passed the kwargs given to the forward function. Default: False

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_full_backward_hook(hook, prepend=False)

Register a backward hook on the module.

The hook will be called every time the gradients with respect to a module are computed, i.e. the hook will execute if and only if the gradients with respect to module outputs are computed. The hook should have the following signature:

hook(module, grad_input, grad_output) -> tuple(Tensor) or None

The grad_input and grad_output are tuples that contain the gradients with respect to the inputs and outputs respectively. The hook should not modify its arguments, but it can optionally return a new gradient with respect to the input that will be used in place of grad_input in subsequent computations. grad_input will only correspond to the inputs given as positional arguments and all kwarg arguments are ignored. Entries in grad_input and grad_output will be None for all non-Tensor arguments.

For technical reasons, when this hook is applied to a Module, its forward function will receive a view of each Tensor passed to the Module. Similarly the caller will receive a view of each Tensor returned by the Module’s forward function.

Warning

Modifying inputs or outputs inplace is not allowed when using backward hooks and will raise an error.

Parameters
  • hook (Callable) – The user-defined hook to be registered.

  • prepend (bool) – If true, the provided hook will be fired before all existing backward hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing backward hooks on this torch.nn.modules.Module. Note that global backward hooks registered with register_module_full_backward_hook() will fire before all hooks registered by this method.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_full_backward_pre_hook(hook, prepend=False)

Register a backward pre-hook on the module.

The hook will be called every time the gradients for the module are computed. The hook should have the following signature:

hook(module, grad_output) -> tuple[Tensor] or None

The grad_output is a tuple. The hook should not modify its arguments, but it can optionally return a new gradient with respect to the output that will be used in place of grad_output in subsequent computations. Entries in grad_output will be None for all non-Tensor arguments.

For technical reasons, when this hook is applied to a Module, its forward function will receive a view of each Tensor passed to the Module. Similarly the caller will receive a view of each Tensor returned by the Module’s forward function.

Warning

Modifying inputs inplace is not allowed when using backward hooks and will raise an error.

Parameters
  • hook (Callable) – The user-defined hook to be registered.

  • prepend (bool) – If true, the provided hook will be fired before all existing backward_pre hooks on this torch.nn.modules.Module. Otherwise, the provided hook will be fired after all existing backward_pre hooks on this torch.nn.modules.Module. Note that global backward_pre hooks registered with register_module_full_backward_pre_hook() will fire before all hooks registered by this method.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_load_state_dict_post_hook(hook)

Register a post hook to be run after module’s load_state_dict is called.

It should have the following signature::

hook(module, incompatible_keys) -> None

The module argument is the current module that this hook is registered on, and the incompatible_keys argument is a NamedTuple consisting of attributes missing_keys and unexpected_keys. missing_keys is a list of str containing the missing keys and unexpected_keys is a list of str containing the unexpected keys.

The given incompatible_keys can be modified inplace if needed.

Note that the checks performed when calling load_state_dict() with strict=True are affected by modifications the hook makes to missing_keys or unexpected_keys, as expected. Additions to either set of keys will result in an error being thrown when strict=True, and clearing out both missing and unexpected keys will avoid an error.

Returns

a handle that can be used to remove the added hook by calling handle.remove()

Return type

torch.utils.hooks.RemovableHandle

register_module(name, module)

Alias for add_module().

Return type

None

register_parameter(name, param)

Add a parameter to the module.

The parameter can be accessed as an attribute using given name.

Parameters
  • name (str) – name of the parameter. The parameter can be accessed from this module using the given name

  • param (Parameter or None) – parameter to be added to the module. If None, then operations that run on parameters, such as cuda, are ignored. If None, the parameter is not included in the module’s state_dict.

Return type

None

register_state_dict_pre_hook(hook)

Register a pre-hook for the load_state_dict() method.

These hooks will be called with arguments: self, prefix, and keep_vars before calling state_dict on self. The registered hooks can be used to perform pre-processing before the state_dict call is made.

requires_grad_(requires_grad=True)

Change if autograd should record operations on parameters in this module.

This method sets the parameters’ requires_grad attributes in-place.

This method is helpful for freezing part of the module for finetuning or training parts of a model individually (e.g., GAN training).

See locally-disable-grad-doc for a comparison between .requires_grad_() and several similar mechanisms that may be confused with it.

Parameters

requires_grad (bool) – whether autograd should record operations on parameters in this module. Default: True.

Returns

self

Return type

Module

save_hyperparameters(*args, ignore=None, frame=None, logger=True)

Save arguments to hparams attribute.

Parameters
  • args (Any) – single object of dict, NameSpace or OmegaConf or string names or arguments from class __init__

  • ignore (Union[str, Sequence[str], None]) – an argument name or a list of argument names from class __init__ to be ignored

  • frame (Optional[frame]) – a frame object. Default is None

  • logger (bool) – Whether to send the hyperparameters to the logger. Default: True

Example::
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class ManuallyArgsModel(HyperparametersMixin):
...     def __init__(self, arg1, arg2, arg3):
...         super().__init__()
...         # manually assign arguments
...         self.save_hyperparameters('arg1', 'arg3')
...     def forward(self, *args, **kwargs):
...         ...
>>> model = ManuallyArgsModel(1, 'abc', 3.14)
>>> model.hparams
"arg1": 1
"arg3": 3.14
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class AutomaticArgsModel(HyperparametersMixin):
...     def __init__(self, arg1, arg2, arg3):
...         super().__init__()
...         # equivalent automatic
...         self.save_hyperparameters()
...     def forward(self, *args, **kwargs):
...         ...
>>> model = AutomaticArgsModel(1, 'abc', 3.14)
>>> model.hparams
"arg1": 1
"arg2": abc
"arg3": 3.14
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class SingleArgModel(HyperparametersMixin):
...     def __init__(self, params):
...         super().__init__()
...         # manually assign single argument
...         self.save_hyperparameters(params)
...     def forward(self, *args, **kwargs):
...         ...
>>> model = SingleArgModel(Namespace(p1=1, p2='abc', p3=3.14))
>>> model.hparams
"p1": 1
"p2": abc
"p3": 3.14
>>> from pytorch_lightning.core.mixins import HyperparametersMixin
>>> class ManuallyArgsModel(HyperparametersMixin):
...     def __init__(self, arg1, arg2, arg3):
...         super().__init__()
...         # pass argument(s) to ignore as a string or in a list
...         self.save_hyperparameters(ignore='arg2')
...     def forward(self, *args, **kwargs):
...         ...
>>> model = ManuallyArgsModel(1, 'abc', 3.14)
>>> model.hparams
"arg1": 1
"arg3": 3.14
Return type

None

set_extra_state(state)

Set extra state contained in the loaded state_dict.

This function is called from load_state_dict() to handle any extra state found within the state_dict. Implement this function and a corresponding get_extra_state() for your module if you need to store extra state within its state_dict.

Parameters

state (dict) – Extra state from the state_dict

set_mc_dropout(active)[source]
set_predict_parameters(n, num_samples, roll_size, batch_size, n_jobs, predict_likelihood_parameters, mc_dropout)[source]

to be set from TorchForecastingModel before calling trainer.predict() and reset at self.on_predict_end()

Return type

None

setup(stage)

Called at the beginning of fit (train + validate), validate, test, or predict. This is a good hook when you need to build models dynamically or adjust something about them. This hook is called on every process when using DDP.

Parameters

stage (str) – either 'fit', 'validate', 'test', or 'predict'

Example:

class LitModel(...):
    def __init__(self):
        self.l1 = None

    def prepare_data(self):
        download_data()
        tokenize()

        # don't do this
        self.something = else

    def setup(self, stage):
        data = load_data(...)
        self.l1 = nn.Linear(28, data.num_classes)
Return type

None

share_memory()

See torch.Tensor.share_memory_().

Return type

~T

state_dict(*args, destination=None, prefix='', keep_vars=False)

Return a dictionary containing references to the whole state of the module.

Both parameters and persistent buffers (e.g. running averages) are included. Keys are corresponding parameter and buffer names. Parameters and buffers set to None are not included.

Note

The returned object is a shallow copy. It contains references to the module’s parameters and buffers.

Warning

Currently state_dict() also accepts positional arguments for destination, prefix and keep_vars in order. However, this is being deprecated and keyword arguments will be enforced in future releases.

Warning

Please avoid the use of argument destination as it is not designed for end-users.

Parameters
  • destination (dict, optional) – If provided, the state of module will be updated into the dict and the same object is returned. Otherwise, an OrderedDict will be created and returned. Default: None.

  • prefix (str, optional) – a prefix added to parameter and buffer names to compose the keys in state_dict. Default: ''.

  • keep_vars (bool, optional) – by default the Tensor s returned in the state dict are detached from autograd. If it’s set to True, detaching will not be performed. Default: False.

Returns

a dictionary containing a whole state of the module

Return type

dict

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> module.state_dict().keys()
['bias', 'weight']
property strict_loading: bool

Determines how Lightning loads this model using .load_state_dict(…, strict=model.strict_loading).

Return type

bool

property supports_probabilistic_prediction: bool
Return type

bool

teardown(stage)

Called at the end of fit (train + validate), validate, test, or predict.

Parameters

stage (str) – either 'fit', 'validate', 'test', or 'predict'

Return type

None

test_dataloader()

An iterable or collection of iterables specifying test samples.

For more information about multiple dataloaders, see this section.

For data processing use the following pattern:

However, the above are only necessary for distributed processing.

Warning

do not assign state in prepare_data

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware. There is no need to set it yourself.

Note

If you don’t need a test dataset and a test_step(), you don’t need to implement this method.

Return type

Any

test_step(*args, **kwargs)

Operates on a single batch of data from the test set. In this step you’d normally generate examples or calculate anything of interest such as accuracy.

Parameters
  • batch – The output of your data iterable, normally a DataLoader.

  • batch_idx – The index of this batch.

  • dataloader_idx – The index of the dataloader that produced this batch. (only if multiple dataloaders used)

Return type

Union[Tensor, Mapping[str, Any], None]

Returns

  • Tensor - The loss tensor

  • dict - A dictionary. Can include any keys, but must include the key 'loss'.

  • None - Skip to the next batch.

# if you have one test dataloader:
def test_step(self, batch, batch_idx): ...

# if you have multiple test dataloaders:
def test_step(self, batch, batch_idx, dataloader_idx=0): ...

Examples:

# CASE 1: A single test dataset
def test_step(self, batch, batch_idx):
    x, y = batch

    # implement your own
    out = self(x)
    loss = self.loss(out, y)

    # log 6 example images
    # or generated text... or whatever
    sample_imgs = x[:6]
    grid = torchvision.utils.make_grid(sample_imgs)
    self.logger.experiment.add_image('example_images', grid, 0)

    # calculate acc
    labels_hat = torch.argmax(out, dim=1)
    test_acc = torch.sum(y == labels_hat).item() / (len(y) * 1.0)

    # log the outputs!
    self.log_dict({'test_loss': loss, 'test_acc': test_acc})

If you pass in multiple test dataloaders, test_step() will have an additional argument. We recommend setting the default value of 0 so that you can quickly switch between single and multiple dataloaders.

# CASE 2: multiple test dataloaders
def test_step(self, batch, batch_idx, dataloader_idx=0):
    # dataloader_idx tells you which dataset this is.
    ...

Note

If you don’t need to test you don’t need to implement this method.

Note

When the test_step() is called, the model has been put in eval mode and PyTorch gradients have been disabled. At the end of the test epoch, the model goes back to training mode and gradients are enabled.

to(*args, **kwargs)

See torch.nn.Module.to().

Return type

Self

to_dtype(dtype)[source]

Cast module precision (float32 by default) to another precision.

to_empty(*, device, recurse=True)

Move the parameters and buffers to the specified device without copying storage.

Parameters
  • device (torch.device) – The desired device of the parameters and buffers in this module.

  • recurse (bool) – Whether parameters and buffers of submodules should be recursively moved to the specified device.

Returns

self

Return type

Module

to_onnx(file_path, input_sample=None, **kwargs)

Saves the model in ONNX format.

Parameters
  • file_path (Union[str, Path]) – The path of the file the onnx model should be saved to.

  • input_sample (Optional[Any]) – An input for tracing. Default: None (Use self.example_input_array)

  • **kwargs – Will be passed to torch.onnx.export function.

Example:

class SimpleModel(LightningModule):
    def __init__(self):
        super().__init__()
        self.l1 = torch.nn.Linear(in_features=64, out_features=4)

    def forward(self, x):
        return torch.relu(self.l1(x.view(x.size(0), -1)

model = SimpleModel()
input_sample = torch.randn(1, 64)
model.to_onnx("export.onnx", input_sample, export_params=True)
Return type

None

to_torchscript(file_path=None, method='script', example_inputs=None, **kwargs)

By default compiles the whole model to a ScriptModule. If you want to use tracing, please provided the argument method='trace' and make sure that either the example_inputs argument is provided, or the model has example_input_array set. If you would like to customize the modules that are scripted you should override this method. In case you want to return multiple modules, we recommend using a dictionary.

Parameters
  • file_path (Union[str, Path, None]) – Path where to save the torchscript. Default: None (no file saved).

  • method (Optional[str]) – Whether to use TorchScript’s script or trace method. Default: ‘script’

  • example_inputs (Optional[Any]) – An input to be used to do tracing when method is set to ‘trace’. Default: None (uses example_input_array)

  • **kwargs – Additional arguments that will be passed to the torch.jit.script() or torch.jit.trace() function.

Note

  • Requires the implementation of the forward() method.

  • The exported script will be set to evaluation mode.

  • It is recommended that you install the latest supported version of PyTorch to use this feature without limitations. See also the torch.jit documentation for supported features.

Example:

class SimpleModel(LightningModule):
    def __init__(self):
        super().__init__()
        self.l1 = torch.nn.Linear(in_features=64, out_features=4)

    def forward(self, x):
        return torch.relu(self.l1(x.view(x.size(0), -1)))

model = SimpleModel()
model.to_torchscript(file_path="model.pt")

torch.jit.save(model.to_torchscript(
    file_path="model_trace.pt", method='trace', example_inputs=torch.randn(1, 64))
)
Return type

Union[ScriptModule, Dict[str, ScriptModule]]

Returns

This LightningModule as a torchscript, regardless of whether file_path is defined or not.

toggle_optimizer(optimizer)

Makes sure only the gradients of the current optimizer’s parameters are calculated in the training step to prevent dangling gradients in multiple-optimizer setup.

It works with untoggle_optimizer() to make sure param_requires_grad_state is properly reset.

Parameters

optimizer (Union[Optimizer, LightningOptimizer]) – The optimizer to toggle.

Return type

None

train(mode=True)

Set the module in training mode.

This has any effect only on certain modules. See documentations of particular modules for details of their behaviors in training/evaluation mode, if they are affected, e.g. Dropout, BatchNorm, etc.

Parameters

mode (bool) – whether to set training mode (True) or evaluation mode (False). Default: True.

Returns

self

Return type

Module

train_dataloader()

An iterable or collection of iterables specifying training samples.

For more information about multiple dataloaders, see this section.

The dataloader you return will not be reloaded unless you set :paramref:`~pytorch_lightning.trainer.trainer.Trainer.reload_dataloaders_every_n_epochs` to a positive integer.

For data processing use the following pattern:

However, the above are only necessary for distributed processing.

Warning

do not assign state in prepare_data

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware. There is no need to set it yourself.

Return type

Any

property trainer: Trainer
Return type

Trainer

training: bool
training_step(train_batch, batch_idx)[source]

performs the training step

Return type

Tensor

transfer_batch_to_device(batch, device, dataloader_idx)

Override this hook if your DataLoader returns tensors wrapped in a custom data structure.

The data types listed below (and any arbitrary nesting of them) are supported out of the box:

  • torch.Tensor or anything that implements .to(…)

  • list

  • dict

  • tuple

For anything else, you need to define how the data is moved to the target device (CPU, GPU, TPU, …).

Note

This hook should only transfer the data and not modify it, nor should it move the data to any other device than the one passed in as argument (unless you know what you are doing). To check the current state of execution of this hook you can use self.trainer.training/testing/validating/predicting so that you can add different logic as per your requirement.

Parameters
  • batch (Any) – A batch of data that needs to be transferred to a new device.

  • device (device) – The target device as defined in PyTorch.

  • dataloader_idx (int) – The index of the dataloader to which the batch belongs.

Return type

Any

Returns

A reference to the data on the new device.

Example:

def transfer_batch_to_device(self, batch, device, dataloader_idx):
    if isinstance(batch, CustomBatch):
        # move all tensors in your custom data structure to the device
        batch.samples = batch.samples.to(device)
        batch.targets = batch.targets.to(device)
    elif dataloader_idx == 0:
        # skip device transfer for the first dataloader or anything you wish
        pass
    else:
        batch = super().transfer_batch_to_device(batch, device, dataloader_idx)
    return batch
Raises

MisconfigurationException – If using IPUs, Trainer(accelerator='ipu').

See also

  • move_data_to_device()

  • apply_to_collection()

type(dst_type)

See torch.nn.Module.type().

Return type

Self

unfreeze()

Unfreeze all parameters for training.

model = MyLightningModule(...)
model.unfreeze()
Return type

None

untoggle_optimizer(optimizer)

Resets the state of required gradients that were toggled with toggle_optimizer().

Parameters

optimizer (Union[Optimizer, LightningOptimizer]) – The optimizer to untoggle.

Return type

None

val_dataloader()

An iterable or collection of iterables specifying validation samples.

For more information about multiple dataloaders, see this section.

The dataloader you return will not be reloaded unless you set :paramref:`~pytorch_lightning.trainer.trainer.Trainer.reload_dataloaders_every_n_epochs` to a positive integer.

It’s recommended that all data downloads and preparation happen in prepare_data().

Note

Lightning tries to add the correct sampler for distributed and arbitrary hardware There is no need to set it yourself.

Note

If you don’t need a validation dataset and a validation_step(), you don’t need to implement this method.

Return type

Any

validation_step(val_batch, batch_idx)[source]

performs the validation step

Return type

Tensor

xpu(device=None)

Move all model parameters and buffers to the XPU.

This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on XPU while being optimized.

Note

This method modifies the module in-place.

Parameters

device (int, optional) – if specified, all parameters will be copied to that device

Returns

self

Return type

Module

zero_grad(set_to_none=True)

Reset gradients of all model parameters.

See similar function under torch.optim.Optimizer for more context.

Parameters

set_to_none (bool) – instead of setting to zero, set the grads to None. See torch.optim.Optimizer.zero_grad() for details.

Return type

None

class darts.models.forecasting.pl_forecasting_module.PLFutureCovariatesModule(input_chunk_length, output_chunk_length, output_chunk_shift=0, train_sample_shape=None, loss_fn=MSELoss(), torch_metrics=None, likelihood=None, optimizer_cls=<class 'torch.optim.adam.Adam'>, optimizer_kwargs=None, lr_scheduler_cls=None, lr_scheduler_kwargs=None, use_reversible_instance_norm=False)[source]

Bases: PLForecastingModule, ABC

PyTorch Lightning-based Forecasting Module.

This class is meant to be inherited to create a new PyTorch Lightning-based forecasting module. When subclassing this class, please make sure to add the following methods with the given signatures:

  • PLForecastingModule.__init__()

  • PLForecastingModule.forward()

  • PLForecastingModule._produce_train_output()

  • PLForecastingModule._get_batch_prediction()

In subclass MyModel’s __init__() function call super(MyModel, self).__init__(**kwargs) where kwargs are the parameters of PLForecastingModule.

Parameters
  • input_chunk_length (int) – Number of time steps in the past to take as a model input (per chunk). Applies to the target series, and past and/or future covariates (if the model supports it).

  • output_chunk_length (int) – Number of time steps predicted at once (per chunk) by the internal model. Also, the number of future values from future covariates to use as a model input (if the model supports future covariates). It is not the same as forecast horizon n used in predict(), which is the desired number of prediction points generated using either a one-shot- or autoregressive forecast. Setting n <= output_chunk_length prevents auto-regression. This is useful when the covariates don’t extend far enough into the future, or to prohibit the model from using future values of past and / or future covariates for prediction (depending on the model’s covariate support).

  • train_sample_shape (Optional[Tuple]) – Shape of the model’s input, used to instantiate model without calling fit_from_dataset and perform sanity check on new training/inference datasets used for re-training or prediction.

  • loss_fn (_Loss) – PyTorch loss function used for training. This parameter will be ignored for probabilistic models if the likelihood parameter is specified. Default: torch.nn.MSELoss().

  • torch_metrics (Union[Metric, MetricCollection, None]) – A torch metric or a MetricCollection used for evaluation. A full list of available metrics can be found at https://torchmetrics.readthedocs.io/en/latest/. Default: None.

  • likelihood (Optional[Likelihood]) – One of Darts’ Likelihood models to be used for probabilistic forecasts. Default: None.

  • optimizer_cls (Optimizer) – The PyTorch optimizer class to be used. Default: torch.optim.Adam.

  • optimizer_kwargs (Optional[Dict]) – Optionally, some keyword arguments for the PyTorch optimizer (e.g., {'lr': 1e-3} for specifying a learning rate). Otherwise the default values of the selected optimizer_cls will be used. Default: None.

  • lr_scheduler_cls (Optional[_LRScheduler]) – Optionally, the PyTorch learning rate scheduler class to be used. Specifying None corresponds to using a constant learning rate. Default: None.

  • lr_scheduler_kwargs (Optional[Dict]) – Optionally, some keyword arguments for the PyTorch learning rate scheduler. Default: None.

  • use_reversible_instance_norm (bool) – Whether to use reversible instance normalization RINorm against distribution shift as shown in [1]. It is only applied to the features of the target series and not the covariates.

References

1

T. Kim et al. “Reversible Instance Normalization for Accurate Time-Series Forecasting against Distribution Shift”, https://openreview.net/forum?id=cGDAkQo1C0p

Attributes

automatic_optimization

If set to False you are responsible for calling .backward(), .step(), .zero_grad().

current_epoch

The current epoch in the Trainer, or 0 if not attached.

example_input_array

The example input array is a specification of what the module can consume in the forward() method.

global_rank

The index of the current process across all nodes and devices.

global_step

Total training batches seen across all epochs.

hparams

The collection of hyperparameters saved with save_hyperparameters().

hparams_initial

The collection of hyperparameters saved with save_hyperparameters().

local_rank

The index of the current process within a single node.

logger

Reference to the logger object in the Trainer.

loggers

Reference to the list of loggers in the Trainer.

on_gpu

Returns True if this model is currently located on a GPU.

output_chunk_length

Number of time steps predicted at once by the model.

strict_loading

Determines how Lightning loads this model using .load_state_dict(..., strict=model.strict_loading).

device

dtype

epochs_trained

fabric

supports_probabilistic_prediction

trainer

Methods

add_module(name, module)

Add a child module to the current module.

all_gather(data[, group, sync_grads])

Gather tensors or collections of tensors from multiple processes.

apply(fn)

Apply fn recursively to every submodule (as returned by .children()) as well as self.

backward(loss, *args, **kwargs)

Called to perform backward on the loss returned in training_step().

bfloat16()

Casts all floating point parameters and buffers to bfloat16 datatype.

buffers([recurse])

Return an iterator over module buffers.

children()

Return an iterator over immediate children modules.

clip_gradients(optimizer[, ...])

Handles gradient clipping internally.

compile(*args, **kwargs)

Compile this Module's forward using torch.compile().

configure_callbacks()

Configure model-specific callbacks.

configure_gradient_clipping(optimizer[, ...])

Perform gradient clipping for the optimizer parameters.

configure_model()

Hook to create modules in a strategy and precision aware context.

configure_optimizers()

configures optimizers and learning rate schedulers for model optimization.

configure_sharded_model()

Deprecated.

configure_torch_metrics(torch_metrics)

process the torch_metrics parameter.

cpu()

See torch.nn.Module.cpu().

cuda([device])

Moves all model parameters and buffers to the GPU.

double()

See torch.nn.Module.double().

eval()

Set the module in evaluation mode.

extra_repr()

Set the extra representation of the module.

float()

See torch.nn.Module.float().

forward(*args, **kwargs)

Same as torch.nn.Module.forward().

freeze()

Freeze all params for inference.

get_buffer(target)

Return the buffer given by target if it exists, otherwise throw an error.

get_extra_state()

Return any extra state to include in the module's state_dict.

get_parameter(target)

Return the parameter given by target if it exists, otherwise throw an error.

get_submodule(target)

Return the submodule given by target if it exists, otherwise throw an error.

half()

See torch.nn.Module.half().

ipu([device])

Move all model parameters and buffers to the IPU.

load_from_checkpoint(checkpoint_path[, ...])

Primary way of loading a model from a checkpoint.

load_state_dict(state_dict[, strict, assign])

Copy parameters and buffers from state_dict into this module and its descendants.

log(name, value[, prog_bar, logger, ...])

Log a key, value pair.

log_dict(dictionary[, prog_bar, logger, ...])

Log a dictionary of values at once.

lr_scheduler_step(scheduler, metric)

Override this method to adjust the default way the Trainer calls each scheduler.

lr_schedulers()

Returns the learning rate scheduler(s) that are being used during training.

manual_backward(loss, *args, **kwargs)

Call this directly from your training_step() when doing optimizations manually.

modules()

Return an iterator over all modules in the network.

named_buffers([prefix, recurse, ...])

Return an iterator over module buffers, yielding both the name of the buffer as well as the buffer itself.

named_children()

Return an iterator over immediate children modules, yielding both the name of the module as well as the module itself.

named_modules([memo, prefix, remove_duplicate])

Return an iterator over all modules in the network, yielding both the name of the module as well as the module itself.

named_parameters([prefix, recurse, ...])

Return an iterator over module parameters, yielding both the name of the parameter as well as the parameter itself.

on_after_backward()

Called after loss.backward() and before optimizers are stepped.

on_after_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch after it is transferred to the device.

on_before_backward(loss)

Called before loss.backward().

on_before_batch_transfer(batch, dataloader_idx)

Override to alter or apply batch augmentations to your batch before it is transferred to the device.

on_before_optimizer_step(optimizer)

Called before optimizer.step().

on_before_zero_grad(optimizer)

Called after training_step() and before optimizer.zero_grad().

on_fit_end()

Called at the very end of fit.

on_fit_start()

Called at the very beginning of fit.

on_load_checkpoint(checkpoint)

Called by Lightning to restore your model.

on_predict_batch_end(outputs, batch, batch_idx)

Called in the predict loop after the batch.

on_predict_batch_start(batch, batch_idx[, ...])

Called in the predict loop before anything happens for that batch.

on_predict_end()

Called at the end of predicting.

on_predict_epoch_end()

Called at the end of predicting.

on_predict_epoch_start()

Called at the beginning of predicting.

on_predict_model_eval()

Called when the predict loop starts.

on_predict_start()

Called at the beginning of predicting.

on_save_checkpoint(checkpoint)

Called by Lightning when saving a checkpoint to give you a chance to store anything else you might want to save.

on_test_batch_end(outputs, batch, batch_idx)

Called in the test loop after the batch.

on_test_batch_start(batch, batch_idx[, ...])

Called in the test loop before anything happens for that batch.

on_test_end()

Called at the end of testing.

on_test_epoch_end()

Called in the test loop at the very end of the epoch.

on_test_epoch_start()

Called in the test loop at the very beginning of the epoch.

on_test_model_eval()

Called when the test loop starts.

on_test_model_train()

Called when the test loop ends.

on_test_start()

Called at the beginning of testing.

on_train_batch_end(outputs, batch, batch_idx)

Called in the training loop after the batch.

on_train_batch_start(batch, batch_idx)

Called in the training loop before anything happens for that batch.

on_train_end()

Called at the end of training before logger experiment is closed.

on_train_epoch_end()

Called in the training loop at the very end of the epoch.

on_train_epoch_start()

Called in the training loop at the very beginning of the epoch.

on_train_start()

Called at the beginning of training after sanity check.

on_validation_batch_end(outputs, batch, ...)

Called in the validation loop after the batch.

on_validation_batch_start(batch, batch_idx)

Called in the validation loop before anything happens for that batch.

on_validation_end()

Called at the end of validation.

on_validation_epoch_end()

Called in the validation loop at the very end of the epoch.

on_validation_epoch_start()

Called in the validation loop at the very beginning of the epoch.

on_validation_model_eval()

Called when the validation loop starts.

on_validation_model_train()

Called when the validation loop ends.

on_validation_model_zero_grad()

Called by the training loop to release gradients before entering the validation loop.

on_validation_start()

Called at the beginning of validation.

optimizer_step(epoch, batch_idx, optimizer)

Override this method to adjust the default way the Trainer calls the optimizer.

optimizer_zero_grad(epoch, batch_idx, optimizer)

Override this method to change the default behaviour of optimizer.zero_grad().

optimizers([use_pl_optimizer])

Returns the optimizer(s) that are being used during training.

parameters([recurse])

Return an iterator over module parameters.

predict_dataloader()

An iterable or collection of iterables specifying prediction samples.

predict_step(batch, batch_idx[, dataloader_idx])

performs the prediction step

prepare_data()

Use this to download and prepare data.

print(*args, **kwargs)

Prints only from process 0.

register_backward_hook(hook)

Register a backward hook on the module.

register_buffer(name, tensor[, persistent])

Add a buffer to the module.

register_forward_hook(hook, *[, prepend, ...])

Register a forward hook on the module.

register_forward_pre_hook(hook, *[, ...])

Register a forward pre-hook on the module.

register_full_backward_hook(hook[, prepend])

Register a backward hook on the module.

register_full_backward_pre_hook(hook[, prepend])

Register a backward pre-hook on the module.

register_load_state_dict_post_hook(hook)

Register a post hook to be run after module's load_state_dict is called.

register_module(name, module)

Alias for add_module().

register_parameter(name, param)

Add a parameter to the module.

register_state_dict_pre_hook(hook)

Register a pre-hook for the load_state_dict() method.

requires_grad_([requires_grad])

Change if autograd should record operations on parameters in this module.

save_hyperparameters(*args[, ignore, frame, ...])

Save arguments to hparams attribute.

set_extra_state(state)

Set extra state contained in the loaded state_dict.

set_predict_parameters(n, num_samples, ...)

to be set from TorchForecastingModel before calling trainer.predict() and reset at self.on_predict_end()

setup(stage)

Called at the beginning of fit (train + validate), validate, test, or predict.

share_memory()

See torch.Tensor.share_memory_().

state_dict(*args[, destination, prefix, ...])

Return a dictionary containing references to the whole state of the module.

teardown(stage)

Called at the end of fit (train + validate), validate, test, or predict.

test_dataloader()

An iterable or collection of iterables specifying test samples.

test_step(*args, **kwargs)

Operates on a single batch of data from the test set.

to(*args, **kwargs)

See torch.nn.Module.to().

to_dtype(dtype)

Cast module precision (float32 by default) to another precision.

to_empty(*, device[, recurse])

Move the parameters and buffers to the specified device without copying storage.

to_onnx(file_path[, input_sample])

Saves the model in ONNX format.

to_torchscript([file_path, method, ...])

By default compiles the whole model to a ScriptModule.

toggle_optimizer(optimizer)

Makes sure only the gradients of the current optimizer's parameters are calculated in the training step to prevent dangling gradients in multiple-optimizer setup.

train([mode])

Set the module in training mode.

train_dataloader()

An iterable or collection of iterables specifying training samples.

training_step(train_batch, batch_idx)

performs the training step

transfer_batch_to_device(batch, device, ...)

Override this hook if your DataLoader returns tensors wrapped in a custom data structure.

type(dst_type)

See torch.nn.Module.type().

unfreeze()

Unfreeze all parameters for training.

untoggle_optimizer(optimizer)

Resets the state of required gradients that were toggled with toggle_optimizer().

val_dataloader()

An iterable or collection of iterables specifying validation samples.

validation_step(val_batch, batch_idx)

performs the validation step

xpu([device])

Move all model parameters and buffers to the XPU.

zero_grad([set_to_none])

Reset gradients of all model parameters.

__call__

set_mc_dropout

CHECKPOINT_HYPER_PARAMS_KEY = 'hyper_parameters'
CHECKPOINT_HYPER_PARAMS_NAME = 'hparams_name'
CHECKPOINT_HYPER_PARAMS_TYPE = 'hparams_type'
T_destination

alias of TypeVar(‘T_destination’, bound=Dict[str, Any])

add_module(name, module)

Add a child module to the current module.

The module can be accessed as an attribute using the given name.

Parameters
  • name (str) – name of the child module. The child module can be accessed from this module using the given name

  • module (Module) – child module to be added to the module.

Return type

None

all_gather(data, group=None, sync_grads=False)

Gather tensors or collections of tensors from multiple processes.

This method needs to be called on all processes and the tensors need to have the same shape across all processes, otherwise your program will stall forever.

Parameters
  • data (Union[Tensor, Dict, List, Tuple]) – int, float, tensor of shape (batch, …), or a (possibly nested) collection thereof.

  • group (Optional[Any]) – the process group to gather results from. Defaults to all processes (world)

  • sync_grads (bool) – flag that allows users to synchronize gradients for the all_gather operation

Return type

Union[Tensor, Dict, List, Tuple]

Returns

A tensor of shape (world_size, batch, …), or if the input was a collection the output will also be a collection with tensors of this shape.

allow_zero_length_dataloader_with_multiple_devices: bool
apply(fn)

Apply fn recursively to every submodule (as returned by .children()) as well as self.

Typical use includes initializing the parameters of a model (see also nn-init-doc).

Parameters

fn (Module -> None) – function to be applied to each submodule

Returns

self

Return type

Module

Example:

>>> @torch.no_grad()
>>> def init_weights(m):
>>>     print(m)
>>>     if type(m) == nn.Linear:
>>>         m.weight.fill_(1.0)
>>>         print(m.weight)
>>> net = nn.Sequential(nn.Linear(2, 2), nn.Linear(2, 2))
>>> net.apply(init_weights)
Linear(in_features=2, out_features=2, bias=True)
Parameter containing:
tensor([[1., 1.],
        [1., 1.]], requires_grad=True)
Linear(in_features=2, out_features=2, bias=True)
Parameter containing:
tensor([[1., 1.],
        [1., 1.]], requires_grad=True)
Sequential(
  (0): Linear(in_features=2, out_features=2, bias=True)
  (1): Linear(in_features=2, out_features=2, bias=True)
)
property automatic_optimization: bool

If set to False you are responsible for calling .backward(), .step(), .zero_grad().

Return type

bool

backward(loss, *args, **kwargs)

Called to perform backward on the loss returned in training_step(). Override this hook with your own implementation if you need to.

Parameters

loss (Tensor) – The loss tensor returned by training_step(). If gradient accumulation is used, the loss here holds the normalized value (scaled by 1 / accumulation steps).

Example:

def backward(self, loss):
    loss.backward()
Return type

None

bfloat16()

Casts all floating point parameters and buffers to bfloat16 datatype.

Note

This method modifies the module in-place.

Returns

self

Return type

Module

buffers(recurse=True)

Return an iterator over module buffers.

Parameters

recurse (bool) – if True, then yields buffers of this module and all submodules. Otherwise, yields only buffers that are direct members of this module.

Yields

torch.Tensor – module buffer

Example:

>>> # xdoctest: +SKIP("undefined vars")
>>> for buf in model.buffers():
>>>     print(type(buf), buf.size())
<class 'torch.Tensor'> (20L,)
<class 'torch.Tensor'> (20L, 1L, 5L, 5L)
Return type

Iterator[Tensor]

call_super_init: bool = False
children()

Return an iterator over immediate children modules.

Yields

Module – a child module

Return type

Iterator[Module]

clip_gradients(optimizer, gradient_clip_val=None, gradient_clip_algorithm=None)

Handles gradient clipping internally.

Note

  • Do not override this method. If you want to customize gradient clipping, consider using configure_gradient_clipping() method.

  • For manual optimization (self.automatic_optimization = False), if you want to use gradient clipping, consider calling self.clip_gradients(opt, gradient_clip_val=0.5, gradient_clip_algorithm="norm") manually in the training step.

Parameters
  • optimizer (Optimizer) – Current optimizer being used.

  • gradient_clip_val (Union[int, float, None]) – The value at which to clip gradients.

  • gradient_clip_algorithm (Optional[str]) – The gradient clipping algorithm to use. Pass gradient_clip_algorithm="value" to clip by value, and gradient_clip_algorithm="norm" to clip by norm.

Return type

None

compile(*args, **kwargs)

Compile this Module’s forward using torch.compile().

This Module’s __call__ method is compiled and all arguments are passed as-is to torch.compile().

See torch.compile() for details on the arguments for this function.

configure_callbacks()

Configure model-specific callbacks. When the model gets attached, e.g., when .fit() or .test() gets called, the list or a callback returned here will be merged with the list of callbacks passed to the Trainer’s callbacks argument. If a callback returned here has the same type as one or several callbacks already present in the Trainer’s callbacks list, it will take priority and replace them. In addition, Lightning will make sure ModelCheckpoint callbacks run last.

Return type

Union[Sequence[Callback], Callback]

Returns

A callback or a list of callbacks which will extend the list of callbacks in the Trainer.

Example:

def configure_callbacks(self):
    early_stop = EarlyStopping(monitor="val_acc", mode="max")
    checkpoint = ModelCheckpoint(monitor="val_loss")
    return [early_stop, checkpoint]
configure_gradient_clipping(optimizer, gradient_clip_val=None, gradient_clip_algorithm=None)

Perform gradient clipping for the optimizer parameters. Called before optimizer_step().

Parameters
  • optimizer (Optimizer) – Current optimizer being used.

  • gradient_clip_val (Union[int, float, None]) – The value at which to clip gradients. By default, value passed in Trainer will be available here.

  • gradient_clip_algorithm (Optional[str]) – The gradient clipping algorithm to use. By default, value passed in Trainer will be available here.

Example:

def configure_gradient_clipping(self, optimizer, gradient_clip_val, gradient_clip_algorithm):
    # Implement your own custom logic to clip gradients
    # You can call `self.clip_gradients` with your settings:
    self.clip_gradients(
        optimizer,
        gradient_clip_val=gradient_clip_val,
        gradient_clip_algorithm=gradient_clip_algorithm
    )
Return type

None

configure_model()

Hook to create modules in a strategy and precision aware context.

This is particularly useful for when using sharded strategies (FSDP and DeepSpeed), where we’d like to shard the model instantly to save memory and initialization time. For non-sharded strategies, you can choose to override this hook or to initialize your model under the init_module() context manager.

This hook is called during each of fit/val/test/predict stages in the same process, so ensure that implementation of this hook is idempotent, i.e., after the first time the hook is called, subsequent calls to it should be a no-op.

Return type

None

configure_optimizers()

configures optimizers and learning rate schedulers for model optimization.

configure_sharded_model()

Deprecated.

Use configure_model() instead.

Return type

None

static configure_torch_metrics(torch_metrics)

process the torch_metrics parameter.

Return type

MetricCollection

cpu()

See torch.nn.Module.cpu().

Return type

Self

cuda(device=None)

Moves all model parameters and buffers to the GPU. This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on GPU while being optimized.

Parameters

device (Union[int, device, None]) – If specified, all parameters will be copied to that device. If None, the current CUDA device index will be used.

Returns

self

Return type

Module

property current_epoch: int

The current epoch in the Trainer, or 0 if not attached.

Return type

int

property device: device
Return type

device

double()

See torch.nn.Module.double().

Return type

Self

property dtype: Union[str, dtype]
Return type

Union[str, dtype]

dump_patches: bool = False
property epochs_trained
eval()

Set the module in evaluation mode.

This has any effect only on certain modules. See documentations of particular modules for details of their behaviors in training/evaluation mode, if they are affected, e.g. Dropout, BatchNorm, etc.

This is equivalent with self.train(False).

See locally-disable-grad-doc for a comparison between .eval() and several similar mechanisms that may be confused with it.

Returns

self

Return type

Module

property example_input_array: Optional[Union[Tensor, Tuple, Dict]]

The example input array is a specification of what the module can consume in the forward() method. The return type is interpreted as follows:

  • Single tensor: It is assumed the model takes a single argument, i.e., model.forward(model.example_input_array)

  • Tuple: The input array should be interpreted as a sequence of positional arguments, i.e., model.forward(*model.example_input_array)

  • Dict: The input array represents named keyword arguments, i.e., model.forward(**model.example_input_array)

Return type

Union[Tensor, Tuple, Dict, None]

extra_repr()

Set the extra representation of the module.

To print customized extra information, you should re-implement this method in your own modules. Both single-line and multi-line strings are acceptable.

Return type

str

property fabric: Optional[Fabric]
Return type

Optional[Fabric]

float()

See torch.nn.Module.float().

Return type

Self

abstract forward(*args, **kwargs)

Same as torch.nn.Module.forward().

Parameters
  • *args – Whatever you decide to pass into the forward method.

  • **kwargs – Keyword arguments are also possible.

Return type

Any

Returns

Your model’s output

freeze()

Freeze all params for inference.

Example:

model = MyLightningModule(...)
model.freeze()
Return type

None

get_buffer(target)

Return the buffer given by target if it exists, otherwise throw an error.

See the docstring for get_submodule for a more detailed explanation of this method’s functionality as well as how to correctly specify target.

Parameters

target (str) – The fully-qualified string name of the buffer to look for. (See get_submodule for how to specify a fully-qualified string.)

Returns

The buffer referenced by target

Return type

torch.Tensor

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not a buffer

get_extra_state()

Return any extra state to include in the module’s state_dict.

Implement this and a corresponding set_extra_state() for your module if you need to store extra state. This function is called when building the module’s state_dict().

Note that extra state should be picklable to ensure working serialization of the state_dict. We only provide provide backwards compatibility guarantees for serializing Tensors; other objects may break backwards compatibility if their serialized pickled form changes.

Returns

Any extra state to store in the module’s state_dict

Return type

object

get_parameter(target)

Return the parameter given by target if it exists, otherwise throw an error.

See the docstring for get_submodule for a more detailed explanation of this method’s functionality as well as how to correctly specify target.

Parameters

target (str) – The fully-qualified string name of the Parameter to look for. (See get_submodule for how to specify a fully-qualified string.)

Returns

The Parameter referenced by target

Return type

torch.nn.Parameter

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not an nn.Parameter

get_submodule(target)

Return the submodule given by target if it exists, otherwise throw an error.

For example, let’s say you have an nn.Module A that looks like this:

A(
    (net_b): Module(
        (net_c): Module(
            (conv): Conv2d(16, 33, kernel_size=(3, 3), stride=(2, 2))
        )
        (linear): Linear(in_features=100, out_features=200, bias=True)
    )
)

(The diagram shows an nn.Module A. A has a nested submodule net_b, which itself has two submodules net_c and linear. net_c then has a submodule conv.)

To check whether or not we have the linear submodule, we would call get_submodule("net_b.linear"). To check whether we have the conv submodule, we would call get_submodule("net_b.net_c.conv").

The runtime of get_submodule is bounded by the degree of module nesting in target. A query against named_modules achieves the same result, but it is O(N) in the number of transitive modules. So, for a simple check to see if some submodule exists, get_submodule should always be used.

Parameters

target (str) – The fully-qualified string name of the submodule to look for. (See above example for how to specify a fully-qualified string.)

Returns

The submodule referenced by target

Return type

torch.nn.Module

Raises

AttributeError – If the target string references an invalid path or resolves to something that is not an nn.Module

property global_rank: int

The index of the current process across all nodes and devices.

Return type

int

property global_step: int

Total training batches seen across all epochs.

If no Trainer is attached, this propery is 0.

Return type

int

half()

See torch.nn.Module.half().

Return type

Self

property hparams: Union[AttributeDict, MutableMapping]

The collection of hyperparameters saved with save_hyperparameters(). It is mutable by the user. For the frozen set of initial hyperparameters, use hparams_initial.

Return type

Union[AttributeDict, MutableMapping]

Returns

Mutable hyperparameters dictionary

property hparams_initial: AttributeDict

The collection of hyperparameters saved with save_hyperparameters(). These contents are read-only. Manual updates to the saved hyperparameters can instead be performed through hparams.

Returns

immutable initial hyperparameters

Return type

AttributeDict

ipu(device=None)

Move all model parameters and buffers to the IPU.

This also makes associated parameters and buffers different objects. So it should be called before constructing optimizer if the module will live on IPU while being optimized.

Note

This method modifies the module in-place.

Parameters

device (int, optional) – if specified, all parameters will be copied to that device

Returns

self

Return type

Module

load_from_checkpoint(checkpoint_path, map_location=None, hparams_file=None, strict=None, **kwargs)

Primary way of loading a model from a checkpoint. When Lightning saves a checkpoint it stores the arguments passed to __init__ in the checkpoint under "hyper_parameters".

Any arguments specified through **kwargs will override args stored in "hyper_parameters".

Parameters
  • checkpoint_path (Union[str, Path, IO]) – Path to checkpoint. This can also be a URL, or file-like object

  • map_location (Union[device, str, int, Callable[[UntypedStorage, str], Optional[UntypedStorage]], Dict[Union[device, str, int], Union[device, str, int]], None]) – If your checkpoint saved a GPU model and you now load on CPUs or a different number of GPUs, use this to map to the new setup. The behaviour is the same as in torch.load().

  • hparams_file (Union[str, Path, None]) –

    Optional path to a .yaml or .csv file with hierarchical structure as in this example:

    drop_prob: 0.2
    dataloader:
        batch_size: 32
    

    You most likely won’t need this since Lightning will always save the hyperparameters to the checkpoint. However, if your checkpoint weights don’t have the hyperparameters saved, use this method to pass in a .yaml file with the hparams you’d like to use. These will be converted into a dict and passed into your LightningModule for use.

    If your model’s hparams argument is Namespace and .yaml file has hierarchical structure, you need to refactor your model to treat hparams as dict.

  • strict (Optional[bool]) – Whether to strictly enforce that the keys in checkpoint_path match the keys returned by this module’s state dict. Defaults to True unless LightningModule.strict_loading is set, in which case it defaults to the value of LightningModule.strict_loading.

  • **kwargs – Any extra keyword args needed to init the model. Can also be used to override saved hyperparameter values.

Return type

Self

Returns

LightningModule instance with loaded weights and hyperparameters (if available).

Note

load_from_checkpoint is a class method. You should use your LightningModule class to call it instead of the LightningModule instance, or a TypeError will be raised.

Note

To ensure all layers can be loaded from the checkpoint, this function will call configure_model() directly after instantiating the model if this hook is overridden in your LightningModule. However, note that load_from_checkpoint does not support loading sharded checkpoints, and you may run out of memory if the model is too large. In this case, consider loading through the Trainer via .fit(ckpt_path=...).

Example:

# load weights without mapping ...
model = MyLightningModule.load_from_checkpoint('path/to/checkpoint.ckpt')

# or load weights mapping all weights from GPU 1 to GPU 0 ...
map_location = {'cuda:1':'cuda:0'}
model = MyLightningModule.load_from_checkpoint(
    'path/to/checkpoint.ckpt',
    map_location=map_location
)

# or load weights and hyperparameters from separate files.
model = MyLightningModule.load_from_checkpoint(
    'path/to/checkpoint.ckpt',
    hparams_file='/path/to/hparams_file.yaml'
)

# override some of the params with new values
model = MyLightningModule.load_from_checkpoint(
    PATH,
    num_layers=128,
    pretrained_ckpt_path=NEW_PATH,
)

# predict
pretrained_model.eval()
pretrained_model.freeze()
y_hat = pretrained_model(x)
load_state_dict(state_dict, strict=True, assign=False)

Copy parameters and buffers from state_dict into this module and its descendants.

If strict is True, then the keys of state_dict must exactly match the keys returned by this module’s state_dict() function.

Warning

If assign is True the optimizer must be created after the call to load_state_dict.

Parameters
  • state_dict (dict) – a dict containing parameters and persistent buffers.

  • strict (bool, optional) – whether to strictly enforce that the keys in state_dict match the keys returned by this module’s state_dict() function. Default: True

  • assign (bool, optional) – whether to assign items in the state dictionary to their corresponding keys in the module instead of copying them inplace into the module’s current parameters and buffers. When False, the properties of the tensors in the current module are preserved while when True, the properties of the Tensors in the state dict are preserved. Default: False

Returns

  • missing_keys is a list of str containing the missing keys

  • unexpected_keys is a list of str containing the unexpected keys

Return type

NamedTuple with missing_keys and unexpected_keys fields

Note

If a parameter or buffer is registered as None and its corresponding key exists in state_dict, load_state_dict() will raise a RuntimeError.

property local_rank: int

The index of the current process within a single node.

Return type

int

log(name, value, prog_bar=False, logger=None, on_step=None, on_epoch=None, reduce_fx='mean', enable_graph=False, sync_dist=False, sync_dist_group=None, add_dataloader_idx=True, batch_size=None, metric_attribute=None, rank_zero_only=False)

Log a key, value pair.

Example:

self.log('train_loss', loss)

The default behavior per hook is documented here: extensions/logging:Automatic Logging.

Parameters
  • name (str) – key to log.

  • value (Union[Metric, Tensor, int,