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Callback

Abstract base class used to build new callbacks.

Abstract base class used to build new callbacks.

class pytorch_lightning.callbacks.base.Callback[source]

Bases: abc.ABC

Abstract base class used to build new callbacks.

Subclass this class and override any of the relevant hooks

on_after_backward(trainer, pl_module)[source]

Called after loss.backward() and before optimizers do anything.

Return type

None

on_batch_end(trainer, pl_module)[source]

Called when the training batch ends.

Return type

None

on_batch_start(trainer, pl_module)[source]

Called when the training batch begins.

Return type

None

on_before_accelerator_backend_setup(trainer, pl_module)[source]

Called before accelerator is being setup

Return type

None

on_before_zero_grad(trainer, pl_module, optimizer)[source]

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

Return type

None

on_epoch_end(trainer, pl_module)[source]

Called when either of train/val/test epoch ends.

Return type

None

on_epoch_start(trainer, pl_module)[source]

Called when either of train/val/test epoch begins.

Return type

None

on_fit_end(trainer, pl_module)[source]

Called when fit ends

Return type

None

on_fit_start(trainer, pl_module)[source]

Called when fit begins

Return type

None

on_init_end(trainer)[source]

Called when the trainer initialization ends, model has not yet been set.

Return type

None

on_init_start(trainer)[source]

Called when the trainer initialization begins, model has not yet been set.

Return type

None

on_keyboard_interrupt(trainer, pl_module)[source]

Called when the training is interrupted by KeyboardInterrupt.

Return type

None

on_load_checkpoint(callback_state)[source]

Called when loading a model checkpoint, use to reload state.

Parameters

callback_state (Dict[str, Any]) – the callback state returned by on_save_checkpoint.

Return type

None

on_pretrain_routine_end(trainer, pl_module)[source]

Called when the pretrain routine ends.

Return type

None

on_pretrain_routine_start(trainer, pl_module)[source]

Called when the pretrain routine begins.

Return type

None

on_sanity_check_end(trainer, pl_module)[source]

Called when the validation sanity check ends.

Return type

None

on_sanity_check_start(trainer, pl_module)[source]

Called when the validation sanity check starts.

Return type

None

on_save_checkpoint(trainer, pl_module, checkpoint)[source]

Called when saving a model checkpoint, use to persist state.

Parameters
  • trainer – the current Trainer instance.

  • pl_module (LightningModule) – the current LightningModule instance.

  • checkpoint (Dict[str, Any]) – the checkpoint dictionary that will be saved.

Return type

dict

Returns

The callback state.

on_test_batch_end(trainer, pl_module, outputs, batch, batch_idx, dataloader_idx)[source]

Called when the test batch ends.

Return type

None

on_test_batch_start(trainer, pl_module, batch, batch_idx, dataloader_idx)[source]

Called when the test batch begins.

Return type

None

on_test_end(trainer, pl_module)[source]

Called when the test ends.

Return type

None

on_test_epoch_end(trainer, pl_module)[source]

Called when the test epoch ends.

Return type

None

on_test_epoch_start(trainer, pl_module)[source]

Called when the test epoch begins.

Return type

None

on_test_start(trainer, pl_module)[source]

Called when the test begins.

Return type

None

on_train_batch_end(trainer, pl_module, outputs, batch, batch_idx, dataloader_idx)[source]

Called when the train batch ends.

Return type

None

on_train_batch_start(trainer, pl_module, batch, batch_idx, dataloader_idx)[source]

Called when the train batch begins.

Return type

None

on_train_end(trainer, pl_module)[source]

Called when the train ends.

Return type

None

on_train_epoch_end(trainer, pl_module, outputs)[source]

Called when the train epoch ends.

Return type

None

on_train_epoch_start(trainer, pl_module)[source]

Called when the train epoch begins.

Return type

None

on_train_start(trainer, pl_module)[source]

Called when the train begins.

Return type

None

on_validation_batch_end(trainer, pl_module, outputs, batch, batch_idx, dataloader_idx)[source]

Called when the validation batch ends.

Return type

None

on_validation_batch_start(trainer, pl_module, batch, batch_idx, dataloader_idx)[source]

Called when the validation batch begins.

Return type

None

on_validation_end(trainer, pl_module)[source]

Called when the validation loop ends.

Return type

None

on_validation_epoch_end(trainer, pl_module)[source]

Called when the val epoch ends.

Return type

None

on_validation_epoch_start(trainer, pl_module)[source]

Called when the val epoch begins.

Return type

None

on_validation_start(trainer, pl_module)[source]

Called when the validation loop begins.

Return type

None

setup(trainer, pl_module, stage)[source]

Called when fit or test begins

Return type

None

teardown(trainer, pl_module, stage)[source]

Called when fit or test ends

Return type

None