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Source code for pytorch_lightning.tuner.tuning

# Copyright The PyTorch Lightning team.
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#     http://www.apache.org/licenses/LICENSE-2.0
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from typing import Any, Dict, Optional, Union

import pytorch_lightning as pl
from pytorch_lightning.trainer.states import TrainerStatus
from pytorch_lightning.tuner.batch_size_scaling import scale_batch_size
from pytorch_lightning.tuner.lr_finder import _LRFinder, lr_find
from pytorch_lightning.utilities.exceptions import MisconfigurationException
from pytorch_lightning.utilities.types import EVAL_DATALOADERS, TRAIN_DATALOADERS


[docs]class Tuner: """Tuner class to tune your model.""" def __init__(self, trainer: "pl.Trainer") -> None: self.trainer = trainer def on_trainer_init(self, auto_lr_find: Union[str, bool], auto_scale_batch_size: Union[str, bool]) -> None: self.trainer.auto_lr_find = auto_lr_find self.trainer.auto_scale_batch_size = auto_scale_batch_size def _tune( self, model: "pl.LightningModule", scale_batch_size_kwargs: Optional[Dict[str, Any]] = None, lr_find_kwargs: Optional[Dict[str, Any]] = None, ) -> Dict[str, Optional[Union[int, _LRFinder]]]: scale_batch_size_kwargs = scale_batch_size_kwargs or {} lr_find_kwargs = lr_find_kwargs or {} # return a dict instead of a tuple so BC is not broken if a new tuning procedure is added result = {} self.trainer.strategy.connect(model) is_tuning = self.trainer.auto_scale_batch_size or self.trainer.auto_lr_find if self.trainer._accelerator_connector.is_distributed and is_tuning: raise MisconfigurationException( "`trainer.tune()` is currently not supported with" f" `Trainer(strategy={self.trainer.strategy.strategy_name!r})`." ) # Run auto batch size scaling if self.trainer.auto_scale_batch_size: if isinstance(self.trainer.auto_scale_batch_size, str): scale_batch_size_kwargs.setdefault("mode", self.trainer.auto_scale_batch_size) result["scale_batch_size"] = scale_batch_size(self.trainer, model, **scale_batch_size_kwargs) # Run learning rate finder: if self.trainer.auto_lr_find: lr_find_kwargs.setdefault("update_attr", True) result["lr_find"] = lr_find(self.trainer, model, **lr_find_kwargs) self.trainer.state.status = TrainerStatus.FINISHED return result def _run(self, *args: Any, **kwargs: Any) -> None: """`_run` wrapper to set the proper state during tuning, as this can be called multiple times.""" self.trainer.state.status = TrainerStatus.RUNNING # last `_run` call might have set it to `FINISHED` self.trainer.training = True self.trainer._run(*args, **kwargs) self.trainer.tuning = True
[docs] def scale_batch_size( self, model: "pl.LightningModule", train_dataloaders: Optional[Union[TRAIN_DATALOADERS, "pl.LightningDataModule"]] = None, val_dataloaders: Optional[EVAL_DATALOADERS] = None, datamodule: Optional["pl.LightningDataModule"] = None, mode: str = "power", steps_per_trial: int = 3, init_val: int = 2, max_trials: int = 25, batch_arg_name: str = "batch_size", ) -> Optional[int]: """Iteratively try to find the largest batch size for a given model that does not give an out of memory (OOM) error. Args: model: Model to tune. train_dataloaders: A collection of :class:`torch.utils.data.DataLoader` or a :class:`~pytorch_lightning.core.datamodule.LightningDataModule` specifying training samples. In the case of multiple dataloaders, please see this :ref:`section <multiple-dataloaders>`. val_dataloaders: A :class:`torch.utils.data.DataLoader` or a sequence of them specifying validation samples. datamodule: An instance of :class:`~pytorch_lightning.core.datamodule.LightningDataModule`. mode: Search strategy to update the batch size: - ``'power'`` (default): Keep multiplying the batch size by 2, until we get an OOM error. - ``'binsearch'``: Initially keep multiplying by 2 and after encountering an OOM error do a binary search between the last successful batch size and the batch size that failed. steps_per_trial: number of steps to run with a given batch size. Ideally 1 should be enough to test if a OOM error occurs, however in practise a few are needed init_val: initial batch size to start the search with max_trials: max number of increase in batch size done before algorithm is terminated batch_arg_name: name of the attribute that stores the batch size. It is expected that the user has provided a model or datamodule that has a hyperparameter with that name. We will look for this attribute name in the following places - ``model`` - ``model.hparams`` - ``trainer.datamodule`` (the datamodule passed to the tune method) """ self.trainer.auto_scale_batch_size = True result = self.trainer.tune( model, train_dataloaders=train_dataloaders, val_dataloaders=val_dataloaders, datamodule=datamodule, scale_batch_size_kwargs={ "mode": mode, "steps_per_trial": steps_per_trial, "init_val": init_val, "max_trials": max_trials, "batch_arg_name": batch_arg_name, }, ) self.trainer.auto_scale_batch_size = False return result["scale_batch_size"]
[docs] def lr_find( self, model: "pl.LightningModule", train_dataloaders: Optional[Union[TRAIN_DATALOADERS, "pl.LightningDataModule"]] = None, val_dataloaders: Optional[EVAL_DATALOADERS] = None, datamodule: Optional["pl.LightningDataModule"] = None, min_lr: float = 1e-8, max_lr: float = 1, num_training: int = 100, mode: str = "exponential", early_stop_threshold: float = 4.0, update_attr: bool = False, ) -> Optional[_LRFinder]: """Enables the user to do a range test of good initial learning rates, to reduce the amount of guesswork in picking a good starting learning rate. Args: model: Model to tune. train_dataloaders: A collection of :class:`torch.utils.data.DataLoader` or a :class:`~pytorch_lightning.core.datamodule.LightningDataModule` specifying training samples. In the case of multiple dataloaders, please see this :ref:`section <multiple-dataloaders>`. val_dataloaders: A :class:`torch.utils.data.DataLoader` or a sequence of them specifying validation samples. datamodule: An instance of :class:`~pytorch_lightning.core.datamodule.LightningDataModule`. min_lr: minimum learning rate to investigate max_lr: maximum learning rate to investigate num_training: number of learning rates to test mode: Search strategy to update learning rate after each batch: - ``'exponential'`` (default): Will increase the learning rate exponentially. - ``'linear'``: Will increase the learning rate linearly. early_stop_threshold: threshold for stopping the search. If the loss at any point is larger than early_stop_threshold*best_loss then the search is stopped. To disable, set to None. update_attr: Whether to update the learning rate attribute or not. Raises: MisconfigurationException: If learning rate/lr in ``model`` or ``model.hparams`` isn't overridden when ``auto_lr_find=True``, or if you are using more than one optimizer. """ self.trainer.auto_lr_find = True result = self.trainer.tune( model, train_dataloaders=train_dataloaders, val_dataloaders=val_dataloaders, datamodule=datamodule, lr_find_kwargs={ "min_lr": min_lr, "max_lr": max_lr, "num_training": num_training, "mode": mode, "early_stop_threshold": early_stop_threshold, "update_attr": update_attr, }, ) self.trainer.auto_lr_find = False return result["lr_find"]

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