class Trainer(
TrainerProperties,
TrainerCallbackHookMixin,
TrainerModelHooksMixin,
TrainerOptimizersMixin,
TrainerLoggingMixin,
TrainerTrainingTricksMixin,
TrainerDataLoadingMixin,
):
@overwrite_by_env_vars
def __init__(
self,
logger: Union[LightningLoggerBase, Iterable[LightningLoggerBase],
bool] = True,
checkpoint_callback: bool = True,
callbacks: Optional[List[Callback]] = None,
default_root_dir: Optional[str] = None,
gradient_clip_val: float = 0,
process_position: int = 0,
num_nodes: int = 1,
num_processes: int = 1,
gpus: Optional[Union[List[int], str, int]] = None,
auto_select_gpus: bool = False,
tpu_cores: Optional[Union[List[int], str, int]] = None,
log_gpu_memory: Optional[str] = None,
progress_bar_refresh_rate: int = 1,
overfit_batches: Union[int, float] = 0.0,
track_grad_norm: Union[int, float, str] = -1,
check_val_every_n_epoch: int = 1,
fast_dev_run: bool = False,
accumulate_grad_batches: Union[int, Dict[int, int], List[list]] = 1,
max_epochs: int = 1000,
min_epochs: int = 1,
max_steps: Optional[int] = None,
min_steps: Optional[int] = None,
limit_train_batches: Union[int, float] = 1.0,
limit_val_batches: Union[int, float] = 1.0,
limit_test_batches: Union[int, float] = 1.0,
val_check_interval: Union[int, float] = 1.0,
flush_logs_every_n_steps: int = 100,
log_every_n_steps: int = 50,
accelerator: Optional[Union[str, Accelerator]] = None,
sync_batchnorm: bool = False,
precision: int = 32,
weights_summary: Optional[str] = 'top',
weights_save_path: Optional[str] = None,
num_sanity_val_steps: int = 2,
truncated_bptt_steps: Optional[int] = None,
resume_from_checkpoint: Optional[str] = None,
profiler: Optional[Union[BaseProfiler, bool, str]] = None,
benchmark: bool = False,
deterministic: bool = False,
reload_dataloaders_every_epoch: bool = False,
auto_lr_find: Union[bool, str] = False,
replace_sampler_ddp: bool = True,
terminate_on_nan: bool = False,
auto_scale_batch_size: Union[str, bool] = False,
prepare_data_per_node: bool = True,
plugins: Optional[list] = None,
amp_backend: str = 'native',
amp_level: str = 'O2',
distributed_backend: Optional[str] = None,
automatic_optimization: bool = True,
):
r"""
Customize every aspect of training via flags
Args:
accelerator: Previously known as distributed_backend (dp, ddp, ddp2, etc...).
Can also take in an accelerator object for custom hardware.
accumulate_grad_batches: Accumulates grads every k batches or as set up in the dict.
amp_backend: The mixed precision backend to use ("native" or "apex")
amp_level: The optimization level to use (O1, O2, etc...).
auto_lr_find: If set to True, will make trainer.tune() run a learning rate finder,
trying to optimize initial learning for faster convergence. trainer.tune() method will
set the suggested learning rate in self.lr or self.learning_rate in the LightningModule.
To use a different key set a string instead of True with the key name.
auto_scale_batch_size: If set to True, will `initially` run a batch size
finder trying to find the largest batch size that fits into memory.
The result will be stored in self.batch_size in the LightningModule.
Additionally, can be set to either `power` that estimates the batch size through
a power search or `binsearch` that estimates the batch size through a binary search.
auto_select_gpus: If enabled and `gpus` is an integer, pick available
gpus automatically. This is especially useful when
GPUs are configured to be in "exclusive mode", such
that only one process at a time can access them.
benchmark: If true enables cudnn.benchmark.
callbacks: Add a list of callbacks.
checkpoint_callback: If ``True``, enable checkpointing.
It will configure a default ModelCheckpoint callback if there is no user-defined ModelCheckpoint in
:paramref:`~pytorch_lightning.trainer.trainer.Trainer.callbacks`. Default: ``True``.
.. warning:: Passing a ModelCheckpoint instance to this argument is deprecated since
v1.1.0 and will be unsupported from v1.4.0.
check_val_every_n_epoch: Check val every n train epochs.
default_root_dir: Default path for logs and weights when no logger/ckpt_callback passed.
Default: ``os.getcwd()``.
Can be remote file paths such as `s3://mybucket/path` or 'hdfs://path/'
deterministic: If true enables cudnn.deterministic.
distributed_backend: deprecated. Please use 'accelerator'
fast_dev_run: runs 1 batch of train, test and val to find any bugs (ie: a sort of unit test).
flush_logs_every_n_steps: How often to flush logs to disk (defaults to every 100 steps).
gpus: number of gpus to train on (int) or which GPUs to train on (list or str) applied per node
gradient_clip_val: 0 means don't clip.
limit_train_batches: How much of training dataset to check (floats = percent, int = num_batches)
limit_val_batches: How much of validation dataset to check (floats = percent, int = num_batches)
limit_test_batches: How much of test dataset to check (floats = percent, int = num_batches)
logger: Logger (or iterable collection of loggers) for experiment tracking.
log_gpu_memory: None, 'min_max', 'all'. Might slow performance
log_every_n_steps: How often to log within steps (defaults to every 50 steps).
automatic_optimization: If False you are responsible for calling .backward, .step, zero_grad.
Meant to be used with multiple optimizers by advanced users.
prepare_data_per_node: If True, each LOCAL_RANK=0 will call prepare data.
Otherwise only NODE_RANK=0, LOCAL_RANK=0 will prepare data
process_position: orders the progress bar when running multiple models on same machine.
progress_bar_refresh_rate: How often to refresh progress bar (in steps). Value ``0`` disables progress bar.
Ignored when a custom callback is passed to :paramref:`~Trainer.callbacks`.
profiler: To profile individual steps during training and assist in identifying bottlenecks. Passing bool
value is deprecated in v1.1 and will be removed in v1.3.
overfit_batches: Overfit a percent of training data (float) or a set number of batches (int). Default: 0.0
plugins: Plugins allow modification of core behavior like ddp and amp.
precision: Full precision (32), half precision (16). Can be used on CPU, GPU or TPUs.
max_epochs: Stop training once this number of epochs is reached.
min_epochs: Force training for at least these many epochs
max_steps: Stop training after this number of steps. Disabled by default (None).
min_steps: Force training for at least these number of steps. Disabled by default (None).
num_nodes: number of GPU nodes for distributed training.
num_sanity_val_steps: Sanity check runs n validation batches before starting the training routine.
Set it to `-1` to run all batches in all validation dataloaders. Default: 2
reload_dataloaders_every_epoch: Set to True to reload dataloaders every epoch.
replace_sampler_ddp: Explicitly enables or disables sampler replacement. If not specified this
will toggled automatically when DDP is used. By default it will add ``shuffle=True`` for
train sampler and ``shuffle=False`` for val/test sampler. If you want to customize it,
you can set ``replace_sampler_ddp=False`` and add your own distributed sampler.
resume_from_checkpoint: To resume training from a specific checkpoint pass in the path here.
This can be a URL.
sync_batchnorm: Synchronize batch norm layers between process groups/whole world.
terminate_on_nan: If set to True, will terminate training (by raising a `ValueError`) at the
end of each training batch, if any of the parameters or the loss are NaN or +/-inf.
tpu_cores: How many TPU cores to train on (1 or 8) / Single TPU to train on [1]
track_grad_norm: -1 no tracking. Otherwise tracks that p-norm. May be set to 'inf' infinity-norm.
truncated_bptt_steps: Truncated back prop breaks performs backprop every k steps of much longer
sequence.
val_check_interval: How often to check the validation set. Use float to check within a training epoch,
use int to check every n steps (batches).
weights_summary: Prints a summary of the weights when training begins.
weights_save_path: Where to save weights if specified. Will override default_root_dir
for checkpoints only. Use this if for whatever reason you need the checkpoints
stored in a different place than the logs written in `default_root_dir`.
Can be remote file paths such as `s3://mybucket/path` or 'hdfs://path/'
Defaults to `default_root_dir`.
"""
super().__init__()
# init connectors
self.dev_debugger = InternalDebugger(self)
self.config_validator = ConfigValidator(self)
self.data_connector = DataConnector(self)
self.optimizer_connector = OptimizerConnector(self)
self.accelerator_connector = AcceleratorConnector(self)
self.logger_connector = LoggerConnector(self)
self.model_connector = ModelConnector(self)
self.precision_connector = PrecisionConnector(self)
self.callback_connector = CallbackConnector(self)
self.debugging_connector = DebuggingConnector(self)
self.training_tricks_connector = TrainingTricksConnector(self)
self.profile_connector = ProfilerConnector(self)
self.checkpoint_connector = CheckpointConnector(self)
self.slurm_connector = SLURMConnector(self)
self.tuner = Tuner(self)
self.accelerator_backend = None
self.evaluation_loop = EvaluationLoop(self)
self.train_loop = TrainLoop(self)
self.plugin_connector = PluginConnector(self)
# training state
self.weights_summary = weights_summary
self.model = None
self.shown_warnings = set()
# init callbacks
# Declare attributes to be set in callback_connector on_trainer_init
self.callback_connector.on_trainer_init(
callbacks,
checkpoint_callback,
progress_bar_refresh_rate,
process_position,
default_root_dir,
weights_save_path,
resume_from_checkpoint,
)
# hook
self.on_init_start()
# init optimizer + lr scheduler related flags
self.optimizer_connector.on_trainer_init()
# init data flags
self.data_connector.on_trainer_init(check_val_every_n_epoch,
reload_dataloaders_every_epoch,
prepare_data_per_node)
# init training tricks
self.training_tricks_connector.on_trainer_init(
gradient_clip_val, track_grad_norm, accumulate_grad_batches,
truncated_bptt_steps, terminate_on_nan)
# init accelerator related flags
self.accelerator_connector.on_trainer_init(
num_processes,
tpu_cores,
accelerator,
distributed_backend,
auto_select_gpus,
gpus,
num_nodes,
log_gpu_memory,
sync_batchnorm,
benchmark,
replace_sampler_ddp,
deterministic,
)
# init train loop related flags
self.train_loop.on_trainer_init(max_epochs, min_epochs, max_steps,
min_steps, num_sanity_val_steps,
automatic_optimization)
self.evaluation_loop.on_trainer_init()
# configure tuner
self.tuner.on_trainer_init(auto_lr_find, auto_scale_batch_size)
# configure profiler
self.profile_connector.on_trainer_init(profiler)
# init logger flags
self.logger_connector.on_trainer_init(logger, flush_logs_every_n_steps,
log_every_n_steps)
# init debugging flags
self.debugging_connector.on_init_start(
limit_train_batches,
limit_val_batches,
limit_test_batches,
val_check_interval,
overfit_batches,
fast_dev_run,
)
# set precision
self.precision_connector.on_trainer_init(precision, amp_level,
amp_backend)
# last thing are the plugins which override whatever the trainer used by default
self.plugin_connector.on_trainer_init(plugins)
# Callback system
self.on_init_end()
def fit(
self,
model: LightningModule,
train_dataloader: Optional[DataLoader] = None,
val_dataloaders: Optional[Union[DataLoader, List[DataLoader]]] = None,
datamodule: Optional[LightningDataModule] = None,
):
r"""
Runs the full optimization routine.
Args:
datamodule: A instance of :class:`LightningDataModule`.
model: Model to fit.
train_dataloader: A Pytorch DataLoader with training samples. If the model has
a predefined train_dataloader method this will be skipped.
val_dataloaders: Either a single Pytorch Dataloader or a list of them, specifying validation samples.
If the model has a predefined val_dataloaders method this will be skipped
"""
# bookkeeping
self._state = TrainerState.RUNNING
# ----------------------------
# LINK DATA
# ----------------------------
# setup data, etc...
self.train_loop.setup_fit(model, train_dataloader, val_dataloaders,
datamodule)
# hook
self.data_connector.prepare_data(model)
# bookkeeping
# we reuse fit in .test() but change its behavior using this flag
self.testing = os.environ.get('PL_TESTING_MODE', self.testing)
# ----------------------------
# SET UP TRAINING
# ----------------------------
self.accelerator_backend = self.accelerator_connector.select_accelerator(
)
self.accelerator_backend.setup(model)
# ----------------------------
# INSPECT THESE FOR MAIN LOOPS
# ----------------------------
# assign training and eval functions... inspect these to see the train and eval loops :)
self.accelerator_backend.train_loop = self.train
self.accelerator_backend.validation_loop = self.run_evaluation
self.accelerator_backend.test_loop = self.run_evaluation
# ----------------------------
# TRAIN
# ----------------------------
# hook
self.call_hook('on_fit_start')
results = self.accelerator_backend.train()
self.accelerator_backend.teardown()
# ----------------------------
# POST-Training CLEAN UP
# ----------------------------
# hook
self.call_hook('on_fit_end')
# hook
self.teardown('fit')
if self.is_function_implemented('teardown'):
model.teardown('fit')
# return 1 when finished
# used for testing or when we need to know that training succeeded
if self._state != TrainerState.INTERRUPTED:
self._state = TrainerState.FINISHED
return results or 1
def train(self):
self.run_sanity_check(self.get_model())
self.checkpoint_connector.has_trained = False
# enable train mode
model = self.get_model()
model.train()
torch.set_grad_enabled(True)
# reload data when needed
self.train_loop.reset_train_val_dataloaders(model)
# hook
self.train_loop.on_train_start()
try:
# run all epochs
for epoch in range(self.current_epoch, self.max_epochs):
# hook
self.train_loop.on_train_epoch_start(epoch)
# run train epoch
self.train_loop.run_training_epoch()
if self.max_steps and self.max_steps <= self.global_step:
# hook
self.train_loop.on_train_end()
return
# update LR schedulers
self.optimizer_connector.update_learning_rates(
interval='epoch')
# early stopping
met_min_epochs = epoch >= self.min_epochs - 1
met_min_steps = self.global_step >= self.min_steps if self.min_steps else True
if self.should_stop:
if met_min_epochs and met_min_steps:
self.train_loop.on_train_end()
return
else:
log.info(
'Trainer was signaled to stop but required minimum epochs'
f' ({self.min_epochs}) or minimum steps ({self.min_steps}) has'
' not been met. Training will continue...')
# hook
self.train_loop.on_train_end()
except KeyboardInterrupt:
rank_zero_warn(
'Detected KeyboardInterrupt, attempting graceful shutdown...')
# user could press ctrl+c many times... only shutdown once
if not self.interrupted:
self.interrupted = True
self._state = TrainerState.INTERRUPTED
self.on_keyboard_interrupt()
# hook
self.train_loop.on_train_end()
def run_evaluation(self, test_mode: bool = False, max_batches=None):
# bookkeeping
self.evaluation_loop.testing = test_mode
dataloaders, max_batches = self.evaluation_loop.get_evaluation_dataloaders(
max_batches)
if self.evaluation_loop.should_skip_evaluation(dataloaders,
max_batches):
return [], []
# enable eval mode + no grads
model = self.get_model()
self.evaluation_loop.on_evaluation_model_eval()
model.zero_grad()
torch.set_grad_enabled(False)
# hook
self.evaluation_loop.on_evaluation_start()
# set up the eval loop
self.evaluation_loop.setup(model, max_batches, dataloaders)
# hook
# TODO: should this be insider the dataloader loop?
self.evaluation_loop.on_evaluation_epoch_start()
# run validation/testing
for dataloader_idx, dataloader in enumerate(dataloaders):
# bookkeeping
dl_outputs = []
dl_step_metrics = []
dataloader = self.accelerator_backend.process_dataloader(
dataloader)
dl_max_batches = self.evaluation_loop.max_batches[dataloader_idx]
for batch_idx, batch in enumerate(dataloader):
if batch is None:
continue
# stop short when running on limited batches
if batch_idx >= dl_max_batches:
break
# hook
self.evaluation_loop.on_evaluation_batch_start(
batch, batch_idx, dataloader_idx)
# lightning module methods
output = self.evaluation_loop.evaluation_step(
test_mode, batch, batch_idx, dataloader_idx)
output = self.evaluation_loop.evaluation_step_end(output)
# hook
self.evaluation_loop.on_evaluation_batch_end(
output, batch, batch_idx, dataloader_idx)
# clean up
self.evaluation_loop.evaluation_batch_end_cleanup(
output, batch_idx, dataloader_idx)
# TODO: deprecate 1.0
self.evaluation_loop.log_evaluation_step_metrics_legacy(
output, batch_idx)
# log step metrics
step_metrics = self.evaluation_loop.log_evaluation_step_metrics(
batch, batch_idx)
if step_metrics is not None:
dl_step_metrics.append(step_metrics)
# track epoch level outputs
if output is not None:
dl_outputs.append(output)
self.evaluation_loop.outputs.append(dl_outputs)
self.evaluation_loop.step_metrics.append(dl_step_metrics)
# lightning module method
deprecated_eval_results, epoch_logs = self.evaluation_loop.evaluation_epoch_end(
num_dataloaders=len(dataloaders))
# bookkeeping
eval_loop_results = self.evaluation_loop.log_epoch_metrics(
deprecated_eval_results, epoch_logs, test_mode)
self.evaluation_loop.predictions.to_disk()
# hook
self.evaluation_loop.on_evaluation_epoch_end()
# enable train mode again
self.evaluation_loop.on_evaluation_model_train()
torch.set_grad_enabled(True)
# hook
self.evaluation_loop.on_evaluation_end()
return eval_loop_results, deprecated_eval_results
def run_test(self):
# only load test dataloader for testing
# self.reset_test_dataloader(ref_model)
eval_loop_results, _ = self.run_evaluation(test_mode=True)
if len(eval_loop_results) == 0:
return 1
# remove the tensors from the eval results
for i, result in enumerate(eval_loop_results):
if isinstance(result, dict):
for k, v in result.items():
if isinstance(v, torch.Tensor):
result[k] = v.cpu().item()
return eval_loop_results
def run_sanity_check(self, ref_model):
using_val_step = ref_model.val_dataloader is not None and is_overridden(
'validation_step', ref_model)
should_sanity_check = using_val_step and self.num_sanity_val_steps > 0 and self.limit_val_batches > 0
# run tiny validation (if validation defined)
# to make sure program won't crash during val
if should_sanity_check:
self.reset_val_dataloader(ref_model)
self.num_sanity_val_batches = [
min(self.num_sanity_val_steps, val_batches)
for val_batches in self.num_val_batches
]
# hook and callback
self.running_sanity_check = True
self.on_sanity_check_start()
# run eval step
_, eval_results = self.run_evaluation(
test_mode=False, max_batches=self.num_sanity_val_batches)
# allow no returns from eval
if eval_results is not None and len(eval_results) > 0:
# when we get a list back, used only the last item
if isinstance(eval_results, list):
eval_results = eval_results[-1]
if isinstance(eval_results, EvalResult):
callback_metrics = eval_results.callback_metrics
else:
_, _, _, callback_metrics, _ = self.process_dict_result(
eval_results)
self.logger_connector.callback_metrics = callback_metrics
self.on_sanity_check_end()
self.running_sanity_check = False
def test(
self,
model: Optional[LightningModule] = None,
test_dataloaders: Optional[Union[DataLoader, List[DataLoader]]] = None,
ckpt_path: Optional[str] = 'best',
verbose: bool = True,
datamodule: Optional[LightningDataModule] = None,
):
r"""
Separates from fit to make sure you never run on your test set until you want to.
Args:
ckpt_path: Either ``best`` or path to the checkpoint you wish to test.
If ``None``, use the weights from the last epoch to test. Default to ``best``.
datamodule: A instance of :class:`LightningDataModule`.
model: The model to test.
test_dataloaders: Either a single
Pytorch Dataloader or a list of them, specifying validation samples.
verbose: If True, prints the test results
Returns:
The final test result dictionary. If no test_epoch_end is defined returns a list of dictionaries
"""
# --------------------
# SETUP HOOK
# --------------------
self.verbose_test = verbose
# If you supply a datamodule you can't supply train_dataloader or val_dataloaders
if test_dataloaders and datamodule:
raise MisconfigurationException(
'You cannot pass test_dataloaders to trainer.test if you supply a datamodule'
)
# Attach datamodule to get setup/prepare_data added to model before the call to it below
self.data_connector.attach_datamodule(model or self.get_model(),
datamodule, 'test')
if model is not None:
results = self.__test_given_model(model, test_dataloaders)
else:
results = self.__test_using_best_weights(ckpt_path,
test_dataloaders)
self.teardown('test')
return results
def __test_using_best_weights(self, ckpt_path, test_dataloaders):
model = self.get_model()
# if user requests the best checkpoint but we don't have it, error
if ckpt_path == 'best' and not self.checkpoint_callback.best_model_path:
raise MisconfigurationException(
'ckpt_path is "best", but ModelCheckpoint is not configured to save the best model.'
)
# load best weights
if ckpt_path is not None:
# ckpt_path is 'best' so load the best model
if ckpt_path == 'best':
ckpt_path = self.checkpoint_callback.best_model_path
if len(ckpt_path) == 0:
rank_zero_warn(
f'.test() found no path for the best weights, {ckpt_path}. Please '
f'specify a path for a checkpoint .test(ckpt_path=PATH)')
return {}
if self.accelerator_backend is not None:
self.accelerator_backend.barrier()
ckpt = pl_load(ckpt_path,
map_location=lambda storage, loc: storage)
model.load_state_dict(ckpt['state_dict'])
# attach dataloaders
if test_dataloaders is not None:
self.data_connector.attach_dataloaders(
model, test_dataloaders=test_dataloaders)
# run tests
self.tested_ckpt_path = ckpt_path
self.testing = True
os.environ['PL_TESTING_MODE'] = '1'
self.model = model
results = self.fit(model)
self.testing = False
del os.environ['PL_TESTING_MODE']
# teardown
if self.is_function_implemented('teardown'):
model_ref = self.get_model()
model_ref.teardown('test')
return results
def __test_given_model(self, model, test_dataloaders):
# attach data
if test_dataloaders is not None:
self.data_connector.attach_dataloaders(
model, test_dataloaders=test_dataloaders)
# run test
# sets up testing so we short circuit to eval
self.testing = True
self.model = model
results = self.fit(model)
self.testing = False
# teardown
if self.is_function_implemented('teardown'):
model.teardown('test')
return results
def tune(
self,
model: LightningModule,
train_dataloader: Optional[DataLoader] = None,
val_dataloaders: Optional[Union[DataLoader, List[DataLoader]]] = None,
datamodule: Optional[LightningDataModule] = None,
):
r"""
Runs routines to tune hyperparameters before training.
Args:
datamodule: A instance of :class:`LightningDataModule`.
model: Model to tune.
train_dataloader: A Pytorch DataLoader with training samples. If the model has
a predefined train_dataloader method this will be skipped.
val_dataloaders: Either a single Pytorch Dataloader or a list of them, specifying validation samples.
If the model has a predefined val_dataloaders method this will be skipped
"""
self.tuner.tune(model, train_dataloader, val_dataloaders, datamodule)
def call_setup_hook(self, model):
# call setup after the ddp process has connected
stage_name = 'test' if self.testing else 'fit'
if self.datamodule is not None:
called = self.datamodule.has_setup_test if self.testing else self.datamodule.has_setup_fit
if not called:
self.datamodule.setup(stage_name)
self.setup(stage_name)
model.setup(stage_name)
def call_hook(self, hook_name, *args, **kwargs):
# always profile hooks
with self.profiler.profile(hook_name):
# first call trainer hook
if hasattr(self, hook_name):
trainer_hook = getattr(self, hook_name)
trainer_hook(*args, **kwargs)
# next call hook in lightningModule
output = None
model_ref = self.get_model()
if is_overridden(hook_name, model_ref):
hook_fx = getattr(model_ref, hook_name)
output = hook_fx(*args, **kwargs)
# if the PL module doesn't have the hook then call the accelator
# used to auto-reduce things for the user with Results obj
elif hasattr(self.accelerator_backend, hook_name):
accelerator_hook = getattr(self.accelerator_backend, hook_name)
output = accelerator_hook(*args, **kwargs)
return output
class Trainer(
TrainerProperties,
TrainerIOMixin,
TrainerCallbackHookMixin,
TrainerModelHooksMixin,
TrainerOptimizersMixin,
TrainerLoggingMixin,
TrainerTrainingTricksMixin,
TrainerDataLoadingMixin,
TrainerDeprecatedAPITillVer0_10,
):
def __init__(
self,
logger: Union[LightningLoggerBase, Iterable[LightningLoggerBase],
bool] = True,
checkpoint_callback: Union[ModelCheckpoint, bool] = True,
early_stop_callback: Optional[Union[EarlyStopping, bool]] = False,
callbacks: Optional[List[Callback]] = None,
default_root_dir: Optional[str] = None,
gradient_clip_val: float = 0,
process_position: int = 0,
num_nodes: int = 1,
num_processes: int = 1,
gpus: Optional[Union[List[int], str, int]] = None,
auto_select_gpus: bool = False,
tpu_cores: Optional[Union[List[int], str, int]] = None,
log_gpu_memory: Optional[str] = None,
progress_bar_refresh_rate: int = 1,
overfit_batches: Union[int, float] = 0.0,
track_grad_norm: Union[int, float, str] = -1,
check_val_every_n_epoch: int = 1,
fast_dev_run: bool = False,
accumulate_grad_batches: Union[int, Dict[int, int],
List[list]] = 1,
max_epochs: int = 1000,
min_epochs: int = 1,
max_steps: Optional[int] = None,
min_steps: Optional[int] = None,
limit_train_batches: Union[int, float] = 1.0,
limit_val_batches: Union[int, float] = 1.0,
limit_test_batches: Union[int, float] = 1.0,
val_check_interval: Union[int, float] = 1.0,
log_save_interval: int = 100,
row_log_interval: int = 50,
distributed_backend: Optional[str] = None,
sync_batchnorm: bool = False,
precision: int = 32,
weights_summary: Optional[str] = ModelSummary.MODE_DEFAULT,
weights_save_path: Optional[str] = None,
num_sanity_val_steps: int = 2,
truncated_bptt_steps: Optional[int] = None,
resume_from_checkpoint: Optional[str] = None,
profiler: Optional[Union[BaseProfiler, bool]] = None,
benchmark: bool = False,
deterministic: bool = False,
reload_dataloaders_every_epoch: bool = False,
auto_lr_find: Union[bool, str] = False,
replace_sampler_ddp: bool = True,
terminate_on_nan: bool = False,
auto_scale_batch_size: Union[str, bool] = False,
prepare_data_per_node: bool = True,
amp_backend: str = 'native',
amp_level: str = 'O2', # backward compatible, todo: remove in v1.0.0
val_percent_check:
float = None, # backward compatible, todo: remove in v0.10.0
test_percent_check:
float = None, # backward compatible, todo: remove in v0.10.0
train_percent_check:
float = None, # backward compatible, todo: remove in v0.10.0
overfit_pct:
float = None, # backward compatible, todo: remove in v1.0.0
):
super().__init__()
# init connectors
self.dev_debugger = InternalDebugger(self)
self.config_validator = ConfigValidator(self)
self.data_connector = DataConnector(self)
self.optimizer_connector = OptimizerConnector(self)
self.accelerator_connector = AcceleratorConnector(self)
self.logger_connector = LoggerConnector(self)
self.model_connector = ModelConnector(self)
self.precision_connector = PrecisionConnector(self)
self.callback_connector = CallbackConnector(self)
self.debugging_connector = DebuggingConnector(self)
self.training_tricks_connector = TrainingTricksConnector(self)
self.profile_connector = ProfilerConnector(self)
self.tuner = Tuner(self)
self.accelerator_backend = None
self.evaluation_loop = EvaluationLoop(self)
self.train_loop = TrainLoop(self)
# training state
self.weights_summary = weights_summary
self.model = None
self.shown_warnings = set()
# init callbacks
self.callback_connector.on_trainer_init(
callbacks, early_stop_callback, checkpoint_callback,
progress_bar_refresh_rate, process_position, default_root_dir,
weights_save_path, resume_from_checkpoint)
# hook
self.on_init_start()
# init optimizer + lr scheduler related flags
self.optimizer_connector.on_trainer_init()
# init data flags
self.data_connector.on_trainer_init(check_val_every_n_epoch,
reload_dataloaders_every_epoch,
prepare_data_per_node)
# init training tricks
self.training_tricks_connector.on_trainer_init(
gradient_clip_val, track_grad_norm, accumulate_grad_batches,
truncated_bptt_steps, terminate_on_nan)
# init accelerator related flags
self.accelerator_connector.on_trainer_init(
num_processes, tpu_cores, distributed_backend, auto_select_gpus,
gpus, num_nodes, log_gpu_memory, sync_batchnorm, benchmark,
replace_sampler_ddp, deterministic)
# init train loop related flags
self.train_loop.on_trainer_init(max_epochs, min_epochs, max_steps,
min_steps, num_sanity_val_steps)
self.evaluation_loop.on_trainer_init()
# configure tuner
self.tuner.on_trainer_init(auto_lr_find, auto_scale_batch_size)
# configure profiler
self.profile_connector.on_trainer_init(profiler)
# init logger flags
self.logger_connector.on_trainer_init(logger, log_save_interval,
row_log_interval)
# init debugging flags
self.debugging_connector.on_init_start(
overfit_pct, val_percent_check, test_percent_check,
train_percent_check, limit_train_batches, limit_val_batches,
limit_test_batches, val_check_interval, overfit_batches,
fast_dev_run)
# set precision
self.precision_connector.on_trainer_init(precision, amp_level,
amp_backend)
# Callback system
self.on_init_end()
def tune(
self,
model: LightningModule,
train_dataloader: Optional[DataLoader] = None,
val_dataloaders: Optional[Union[DataLoader, List[DataLoader]]] = None,
datamodule: Optional[LightningDataModule] = None,
):
# TODO: temporary, need to decide if tune or separate object
# setup data, etc...
self.train_loop.setup_fit(model, train_dataloader, val_dataloaders,
datamodule)
# hook
self.data_connector.prepare_data(model)
# Run auto batch size scaling
if self.auto_scale_batch_size:
if isinstance(self.auto_scale_batch_size, bool):
self.auto_scale_batch_size = 'power'
self.tuner.scale_batch_size(
model,
mode=self.auto_scale_batch_size,
train_dataloader=train_dataloader,
val_dataloaders=val_dataloaders,
datamodule=datamodule,
)
model.logger = self.logger # reset logger binding
# Run learning rate finder:
if self.auto_lr_find:
self.tuner.internal_find_lr(self, model)
model.logger = self.logger # reset logger binding
# -----------------------------
# MODEL TRAINING
# -----------------------------
@trainer_state(entering=TrainerState.RUNNING,
exiting=TrainerState.FINISHED)
def fit(
self,
model: LightningModule,
train_dataloader: Optional[DataLoader] = None,
val_dataloaders: Optional[Union[DataLoader, List[DataLoader]]] = None,
datamodule: Optional[LightningDataModule] = None,
):
# setup data, etc...
self.train_loop.setup_fit(model, train_dataloader, val_dataloaders,
datamodule)
# hook
self.call_hook('on_fit_start', model)
# hook
self.data_connector.prepare_data(model)
# set testing if set in environ
self.testing = os.environ.get('PL_TESTING_MODE', self.testing)
# -------------------------
# TRAIN
# -------------------------
self.accelerator_backend = self.accelerator_connector.select_accelerator(
)
self.accelerator_backend.setup(model)
results = self.accelerator_backend.train()
self.accelerator_backend.teardown()
# -------------------------
# POST-Training
# -------------------------
# hook
self.call_hook('on_fit_end')
# hook
self.teardown('fit')
if self.is_function_implemented('teardown'):
model.teardown('fit')
# return 1 when finished
# used for testing or when we need to know that training succeeded
return results or 1
def train(self):
self.run_sanity_check(self.get_model())
# enable train mode
model = self.get_model()
model.train()
torch.set_grad_enabled(True)
# reload data when needed
self.train_loop.reset_train_val_dataloaders(model)
# hook
self.train_loop.on_train_start()
try:
# run all epochs
for epoch in range(self.current_epoch, self.max_epochs):
# reset train dataloader
if self.reload_dataloaders_every_epoch:
self.reset_train_dataloader(model)
# hook
self.train_loop.on_train_epoch_start(epoch)
# run train epoch
self.train_loop.run_training_epoch()
if self.max_steps and self.max_steps <= self.global_step:
# hook
self.train_loop.on_train_end()
return
# update LR schedulers
self.optimizer_connector.update_learning_rates(
interval='epoch')
# early stopping
met_min_epochs = epoch >= self.min_epochs - 1
met_min_steps = self.global_step >= self.min_steps if self.min_steps else True
if self.should_stop:
if (met_min_epochs and met_min_steps):
self.train_loop.on_train_end()
return
else:
log.info(
'Trainer was signaled to stop but required minimum epochs'
f' ({self.min_epochs}) or minimum steps ({self.min_steps}) has'
' not been met. Training will continue...')
# hook
self.train_loop.on_train_end()
except KeyboardInterrupt:
rank_zero_warn(
'Detected KeyboardInterrupt, attempting graceful shutdown...')
# user could press ctrl+c many times... only shutdown once
if not self.interrupted:
self.interrupted = True
self._state = TrainerState.INTERRUPTED
self.on_keyboard_interrupt()
# hook
self.train_loop.on_train_end()
def run_evaluation(self, test_mode: bool = False, max_batches=None):
# bookkeeping
self.evaluation_loop.testing = test_mode
dataloaders, max_batches = self.evaluation_loop.get_evaluation_dataloaders(
max_batches)
if self.evaluation_loop.should_skip_evaluation(dataloaders,
max_batches):
return [], []
# enable eval mode + no grads
model = self.get_model()
model.zero_grad()
model.eval()
torch.set_grad_enabled(False)
# hook
self.evaluation_loop.on_evaluation_start()
# set up the eval loop
self.evaluation_loop.setup(model, max_batches, dataloaders)
# hook
# TODO: should this be insider the dataloader loop?
self.evaluation_loop.on_evaluation_epoch_start()
# run validation/testing
for dataloader_idx, dataloader in enumerate(dataloaders):
# bookkeeping
dl_outputs = []
dataloader = self.accelerator_backend.process_dataloader(
dataloader)
dl_max_batches = self.evaluation_loop.max_batches[dataloader_idx]
for batch_idx, batch in enumerate(dataloader):
if batch is None:
continue
# stop short when running on limited batches
if batch_idx >= dl_max_batches:
break
# hook
self.evaluation_loop.on_evaluation_batch_start(
batch, batch_idx, dataloader_idx)
# lightning module methods
output = self.evaluation_loop.evaluation_step(
test_mode, batch, batch_idx, dataloader_idx)
output = self.evaluation_loop.evaluation_step_end(output)
# hook
self.evaluation_loop.on_evaluation_batch_end(
batch, batch_idx, dataloader_idx)
# clean up
self.evaluation_loop.evaluation_batch_end_cleanup(
output, batch_idx, dataloader_idx)
self.evaluation_loop.log_step_metrics(output, batch_idx)
# track epoch level metrics
if output is not None:
dl_outputs.append(output)
self.evaluation_loop.outputs.append(dl_outputs)
# lightning module method
eval_results = self.evaluation_loop.evaluation_epoch_end(
num_dataloaders=len(dataloaders))
# bookkeeping
eval_loop_results = self.evaluation_loop.log_epoch_metrics(
eval_results, test_mode)
self.evaluation_loop.predictions.to_disk()
# hook
self.evaluation_loop.on_evaluation_epoch_end()
# enable train mode again
model.train()
torch.set_grad_enabled(True)
# hook
self.evaluation_loop.on_evaluation_end()
return eval_loop_results, eval_results
def run_test(self):
# only load test dataloader for testing
# self.reset_test_dataloader(ref_model)
eval_loop_results, _ = self.run_evaluation(test_mode=True)
if len(eval_loop_results) == 0:
return 1
# remove the tensors from the eval results
for i, result in enumerate(eval_loop_results):
if isinstance(result, dict):
for k, v in result.items():
if isinstance(v, torch.Tensor):
result[k] = v.cpu().item()
return eval_loop_results
def run_sanity_check(self, ref_model):
using_val_step = ref_model.val_dataloader is not None and is_overridden(
'validation_step', ref_model)
should_sanity_check = using_val_step and self.num_sanity_val_steps > 0 and self.limit_val_batches > 0
# run tiny validation (if validation defined)
# to make sure program won't crash during val
if should_sanity_check:
self.reset_val_dataloader(ref_model)
self.num_sanity_val_batches = [
min(self.num_sanity_val_steps, val_batches)
for val_batches in self.num_val_batches
]
# hook and callback
self.running_sanity_check = True
self.on_sanity_check_start()
# run eval step
_, eval_results = self.run_evaluation(
test_mode=False, max_batches=self.num_sanity_val_batches)
# allow no returns from eval
if eval_results is not None and len(eval_results) > 0:
# when we get a list back, used only the last item
if isinstance(eval_results, list):
eval_results = eval_results[-1]
if isinstance(eval_results, EvalResult):
callback_metrics = eval_results.callback_metrics
else:
_, _, _, callback_metrics, _ = self.process_output(
eval_results)
self.logger_connector.callback_metrics = callback_metrics
self.on_sanity_check_end()
self.running_sanity_check = False
@trainer_state(entering=TrainerState.RUNNING,
exiting=TrainerState.FINISHED)
def test(
self,
model: Optional[LightningModule] = None,
test_dataloaders: Optional[Union[DataLoader, List[DataLoader]]] = None,
ckpt_path: Optional[str] = 'best',
verbose: bool = True,
datamodule: Optional[LightningDataModule] = None,
):
# --------------------
# SETUP HOOK
# --------------------
self.verbose_test = verbose
if self.global_rank != 0:
return
# If you supply a datamodule you can't supply train_dataloader or val_dataloaders
if test_dataloaders and datamodule:
raise MisconfigurationException(
'You cannot pass test_dataloaders to trainer.test if you supply a datamodule'
)
# Attach datamodule to get setup/prepare_data added to model before the call to it below
self.data_connector.attach_datamodule(model or self.get_model(),
datamodule, 'test')
if model is not None:
results = self.__test_given_model(model, test_dataloaders)
else:
results = self.__test_using_best_weights(ckpt_path,
test_dataloaders)
self.teardown('test')
return results
def __test_using_best_weights(self, ckpt_path, test_dataloaders):
model = self.get_model()
# if user requests the best checkpoint but we don't have it, error
if ckpt_path == 'best' and self.checkpoint_callback.save_top_k <= 0:
raise MisconfigurationException(
'ckpt_path is "best", but ModelCheckpoint is not configured to save the best model.'
)
# load best weights
if ckpt_path is not None:
# ckpt_path is 'best' so load the best model
if ckpt_path == 'best':
ckpt_path = self.checkpoint_callback.best_model_path
if len(ckpt_path) == 0:
rank_zero_warn(
f'.test() found no path for the best weights, {ckpt_path}. Please '
f'specify a path for a checkpoint .test(ckpt_path=PATH)')
return {}
ckpt = torch.load(ckpt_path,
map_location=lambda storage, loc: storage)
model.load_state_dict(ckpt['state_dict'])
# attach dataloaders
if test_dataloaders is not None:
self.data_connector.attach_dataloaders(
model, test_dataloaders=test_dataloaders)
# run tests
self.tested_ckpt_path = ckpt_path
self.testing = True
os.environ['PL_TESTING_MODE'] = '1'
self.model = model
results = self.fit(model)
self.testing = False
del os.environ['PL_TESTING_MODE']
# teardown
if self.is_function_implemented('teardown'):
model_ref = self.get_model()
model_ref.teardown('test')
return results
def __test_given_model(self, model, test_dataloaders):
# attach data
if test_dataloaders is not None:
self.data_connector.attach_dataloaders(
model, test_dataloaders=test_dataloaders)
# run test
# sets up testing so we short circuit to eval
self.testing = True
self.model = model
results = self.fit(model)
self.testing = False
# teardown
if self.is_function_implemented('teardown'):
model.teardown('test')
return results
def call_setup_hook(self, model):
# call setup after the ddp process has connected
stage_name = 'test' if self.testing else 'fit'
if self.datamodule is not None:
called = self.datamodule.has_setup_test if self.testing else self.datamodule.has_setup_fit
if not called:
self.datamodule.setup(stage_name)
self.setup(stage_name)
model.setup(stage_name)
def call_hook(self, hook_name, *args, **kwargs):
# always profile hooks
with self.profiler.profile(hook_name):
# first call trainer hook
if hasattr(self, hook_name):
trainer_hook = getattr(self, hook_name)
trainer_hook(*args, **kwargs)
# next call hook in lightningModule
output = None
model_ref = self.get_model()
if is_overridden(hook_name, model_ref):
hook_fx = getattr(model_ref, hook_name)
output = hook_fx(*args, **kwargs)
# if the PL module doesn't have the hook then call the accelator
# used to auto-reduce things for the user with Results obj
elif hasattr(self.accelerator_backend, hook_name):
accelerator_hook = getattr(self.accelerator_backend, hook_name)
output = accelerator_hook(*args, **kwargs)
return output
