def gen_save_best_models_by_val_score(
save_handler: Union[Callable, BaseSaveHandler],
evaluator: Engine,
models: Union[torch.nn.Module, Dict[str, torch.nn.Module]],
metric_name: str,
n_saved: int = 3,
trainer: Optional[Engine] = None,
tag: str = "val",
**kwargs: Any,
) -> Checkpoint:
"""Method adds a handler to ``evaluator`` to save ``n_saved`` of best models based on the metric
(named by ``metric_name``) provided by ``evaluator`` (i.e. ``evaluator.state.metrics[metric_name]``).
Models with highest metric value will be retained. The logic of how to store objects is delegated to
``save_handler``.
Args:
save_handler: Method or callable class to
use to save engine and other provided objects. Function receives two objects: checkpoint as a dictionary
and filename. If ``save_handler`` is callable class, it can
inherit of :class:`~ignite.handlers.checkpoint.BaseSaveHandler` and optionally implement ``remove`` method
to keep a fixed number of saved checkpoints. In case if user needs to save engine's checkpoint on a disk,
``save_handler`` can be defined with :class:`~ignite.handlers.DiskSaver`.
evaluator: evaluation engine used to provide the score
models: model or dictionary with the object to save. Objects should have
implemented ``state_dict`` and ``load_state_dict`` methods.
metric_name: metric name to use for score evaluation. This metric should be present in
`evaluator.state.metrics`.
n_saved: number of best models to store
trainer: trainer engine to fetch the epoch when saving the best model.
tag: score name prefix: `{tag}_{metric_name}`. By default, tag is "val".
kwargs: optional keyword args to be passed to construct :class:`~ignite.handlers.Checkpoint`.
Returns:
A :class:`~ignite.handlers.Checkpoint` handler.
"""
global_step_transform = None
if trainer is not None:
global_step_transform = global_step_from_engine(trainer)
if isinstance(models, nn.Module):
to_save = {"model": models} # type: Dict[str, nn.Module]
else:
to_save = models
best_model_handler = Checkpoint(
to_save,
save_handler,
filename_prefix="best",
n_saved=n_saved,
global_step_transform=global_step_transform,
score_name=f"{tag}_{metric_name.lower()}",
score_function=Checkpoint.get_default_score_fn(metric_name),
**kwargs,
)
evaluator.add_event_handler(Events.COMPLETED, best_model_handler)
return best_model_handler
def training(local_rank, config):
rank = idist.get_rank()
manual_seed(config["seed"] + rank)
device = idist.device()
logger = setup_logger(name="CIFAR10-Training", distributed_rank=local_rank)
log_basic_info(logger, config)
output_path = config["output_path"]
if rank == 0:
if config["stop_iteration"] is None:
now = datetime.now().strftime("%Y%m%d-%H%M%S")
else:
now = f"stop-on-{config['stop_iteration']}"
folder_name = f"{config['model']}_backend-{idist.backend()}-{idist.get_world_size()}_{now}"
output_path = Path(output_path) / folder_name
if not output_path.exists():
output_path.mkdir(parents=True)
config["output_path"] = output_path.as_posix()
logger.info(f"Output path: {config['output_path']}")
if "cuda" in device.type:
config["cuda device name"] = torch.cuda.get_device_name(local_rank)
if config["with_clearml"]:
try:
from clearml import Task
except ImportError:
# Backwards-compatibility for legacy Trains SDK
from trains import Task
task = Task.init("CIFAR10-Training", task_name=output_path.stem)
task.connect_configuration(config)
# Log hyper parameters
hyper_params = [
"model",
"batch_size",
"momentum",
"weight_decay",
"num_epochs",
"learning_rate",
"num_warmup_epochs",
]
task.connect({k: config[k] for k in hyper_params})
# Setup dataflow, model, optimizer, criterion
train_loader, test_loader = get_dataflow(config)
config["num_iters_per_epoch"] = len(train_loader)
model, optimizer, criterion, lr_scheduler = initialize(config)
# Create trainer for current task
trainer = create_trainer(model, optimizer, criterion, lr_scheduler, train_loader.sampler, config, logger)
# Let's now setup evaluator engine to perform model's validation and compute metrics
metrics = {
"Accuracy": Accuracy(),
"Loss": Loss(criterion),
}
# We define two evaluators as they wont have exactly similar roles:
# - `evaluator` will save the best model based on validation score
evaluator = create_evaluator(model, metrics=metrics, config=config)
train_evaluator = create_evaluator(model, metrics=metrics, config=config)
def run_validation(engine):
epoch = trainer.state.epoch
state = train_evaluator.run(train_loader)
log_metrics(logger, epoch, state.times["COMPLETED"], "Train", state.metrics)
state = evaluator.run(test_loader)
log_metrics(logger, epoch, state.times["COMPLETED"], "Test", state.metrics)
trainer.add_event_handler(Events.EPOCH_COMPLETED(every=config["validate_every"]) | Events.COMPLETED, run_validation)
if rank == 0:
# Setup TensorBoard logging on trainer and evaluators. Logged values are:
# - Training metrics, e.g. running average loss values
# - Learning rate
# - Evaluation train/test metrics
evaluators = {"training": train_evaluator, "test": evaluator}
tb_logger = common.setup_tb_logging(output_path, trainer, optimizer, evaluators=evaluators)
# Store 2 best models by validation accuracy starting from num_epochs / 2:
best_model_handler = Checkpoint(
{"model": model},
get_save_handler(config),
filename_prefix="best",
n_saved=2,
global_step_transform=global_step_from_engine(trainer),
score_name="test_accuracy",
score_function=Checkpoint.get_default_score_fn("Accuracy"),
)
evaluator.add_event_handler(
Events.COMPLETED(lambda *_: trainer.state.epoch > config["num_epochs"] // 2), best_model_handler
)
# In order to check training resuming we can stop training on a given iteration
if config["stop_iteration"] is not None:
@trainer.on(Events.ITERATION_STARTED(once=config["stop_iteration"]))
def _():
logger.info(f"Stop training on {trainer.state.iteration} iteration")
trainer.terminate()
try:
trainer.run(train_loader, max_epochs=config["num_epochs"])
except Exception as e:
logger.exception("")
raise e
if rank == 0:
tb_logger.close()
def training(local_rank, config):
rank = idist.get_rank()
manual_seed(config["seed"] + rank)
device = idist.device()
logger = setup_logger(name="CIFAR10-Training", distributed_rank=local_rank)
log_basic_info(logger, config)
output_path = config["output_path"]
if rank == 0:
now = datetime.now().strftime("%Y%m%d-%H%M%S")
folder_name = f"{config['model']}_backend-{idist.backend()}-{idist.get_world_size()}_{now}"
output_path = Path(output_path) / folder_name
if not output_path.exists():
output_path.mkdir(parents=True)
config["output_path"] = output_path.as_posix()
logger.info(f"Output path: {config['output_path']}")
if "cuda" in device.type:
config["cuda device name"] = torch.cuda.get_device_name(local_rank)
if config["with_clearml"]:
try:
from clearml import Task
except ImportError:
# Backwards-compatibility for legacy Trains SDK
from trains import Task
task = Task.init("CIFAR10-Training", task_name=output_path.stem)
task.connect_configuration(config)
task.connect(config)
# Setup dataflow, model, optimizer, criterion
train_loader, test_loader = get_dataflow(config)
config["num_iters_per_epoch"] = len(train_loader)
model, optimizer, criterion, lr_scheduler = initialize(config)
logger.info(
f"# model parameters (M): {sum([m.numel() for m in model.parameters()]) * 1e-6}"
)
# Create trainer for current task
trainer = create_trainer(model, optimizer, criterion, lr_scheduler,
train_loader.sampler, config, logger)
# Let's now setup evaluator engine to perform model's validation and
# compute metrics
metrics = {
"Accuracy": Accuracy(),
"Loss": Loss(criterion),
}
# We define two evaluators as they wont have exactly similar roles:
# - `evaluator` will save the best model based on validation score
evaluator = create_evaluator(model, metrics=metrics, config=config)
train_evaluator = create_evaluator(model, metrics=metrics, config=config)
if config["smoke_test"]:
logger.info(
"Reduce the size of training and test dataloader as smoke_test=True"
)
def get_batches(loader):
loader_iter = iter(loader)
return [next(loader_iter) for _ in range(5)]
train_loader = get_batches(train_loader)
test_loader = get_batches(test_loader)
if config["with_pbar"] and rank == 0:
ProgressBar(desc="Evaluation (train)",
persist=False).attach(train_evaluator)
ProgressBar(desc="Evaluation (val)", persist=False).attach(evaluator)
def run_validation(engine):
epoch = trainer.state.epoch
state = train_evaluator.run(train_loader)
log_metrics(logger, epoch, state.times["COMPLETED"], "Train",
state.metrics)
state = evaluator.run(test_loader)
log_metrics(logger, epoch, state.times["COMPLETED"], "Test",
state.metrics)
trainer.add_event_handler(
Events.EPOCH_COMPLETED(every=config["validate_every"])
| Events.COMPLETED,
run_validation,
)
if rank == 0:
# Setup TensorBoard logging on trainer and evaluators. Logged values are:
# - Training metrics, e.g. running average loss values
# - Learning rate
# - Evaluation train/test metrics
evaluators = {"training": train_evaluator, "test": evaluator}
tb_logger = common.setup_tb_logging(output_path,
trainer,
optimizer,
evaluators=evaluators)
# Store 1 best models by validation accuracy starting from num_epochs / 2:
best_model_handler = Checkpoint(
{"model": model},
get_save_handler(config),
filename_prefix="best",
n_saved=1,
global_step_transform=global_step_from_engine(trainer),
score_name="test_accuracy",
score_function=Checkpoint.get_default_score_fn("Accuracy"),
)
evaluator.add_event_handler(
Events.COMPLETED(
lambda *_: trainer.state.epoch > config["num_epochs"] // 2),
best_model_handler,
)
try:
trainer.run(train_loader, max_epochs=config["num_epochs"])
except Exception as e:
logger.exception("")
raise e
if rank == 0:
tb_logger.close()
to_save, save_handler, filename_prefix="training")
# Attach the handler to the trainer
trainer.add_event_handler(Events.EPOCH_COMPLETED, checkpoint_handler)
# Store best model by validation accuracy
best_model_handler = Checkpoint(
{"model": model},
save_handler,
filename_prefix="best",
n_saved=1,
score_name="accuracy",
score_function=Checkpoint.get_default_score_fn("accuracy"),
)
evaluator.add_event_handler(Events.COMPLETED, best_model_handler)
# ### Setting up TensorBoard as an experiment tracking system
tb_logger = TensorboardLogger(log_dir=output_path)
# Attach handler to plot trainer's loss every 100 iterations
tb_logger.attach_output_handler(
