holocron.trainer¶

holocron.trainer provides some basic objects for training purposes.

class holocron.trainer.Trainer(model: Module, train_loader: DataLoader, val_loader: DataLoader, criterion: Module, optimizer: Optimizer, gpu: int | None = None, output_file: str = './checkpoint.pth', amp: bool = False, skip_nan_loss: bool = False, nan_tolerance: int = 5, gradient_acc: int = 1, gradient_clip: float | None = None, on_epoch_end: Callable[[Dict[str, float]], Any] | None = None)[source]¶

Baseline trainer class.

Parameters:

model – model to train
train_loader – training loader
val_loader – validation loader
criterion – loss criterion
optimizer – parameter optimizer
gpu – index of the GPU to use
output_file – path where checkpoints will be saved
amp – whether to use automatic mixed precision
skip_nan_loss – whether the optimizer step should be skipped when the loss is NaN
nan_tolerance – number of consecutive batches with NaN loss before stopping the training
gradient_acc – number of batches to accumulate the gradient of before performing the update step
gradient_clip – the gradient clip value
on_epoch_end – callback triggered at the end of an epoch

check_setup(freeze_until: str | None = None, lr: float = 0.0003, norm_weight_decay: float | None = None, num_it: int = 100, **kwargs: Any) → None[source]¶

Check whether you can overfit one batch

Parameters:

freeze_until (str, optional) – last layer to freeze
lr (float, optional) – learning rate to be used for training
norm_weight_decay (float, optional) – weight decay to apply to normalization parameters
num_it (int, optional) – number of iterations to perform
kwargs – keyword args of matplotlib.pyplot.show

find_lr(freeze_until: str | None = None, start_lr: float = 1e-07, end_lr: float = 1, norm_weight_decay: float | None = None, num_it: int = 100) → None[source]¶

Gridsearch the optimal learning rate for the training as described in “Cyclical Learning Rates for Training Neural Networks”.

Parameters:

freeze_until (str, optional) – last layer to freeze
start_lr (float, optional) – initial learning rate
end_lr (float, optional) – final learning rate
norm_weight_decay (float, optional) – weight decay to apply to normalization parameters
num_it (int, optional) – number of iterations to perform

fit_n_epochs(num_epochs: int, lr: float, freeze_until: str | None = None, sched_type: str = 'onecycle', norm_weight_decay: float | None = None, **kwargs: Any) → None[source]¶

Train the model for a given number of epochs.

Parameters:

num_epochs (int) – number of epochs to train
lr (float) – learning rate to be used by the scheduler
freeze_until (str, optional) – last layer to freeze
sched_type (str, optional) – type of scheduler to use
norm_weight_decay (float, optional) – weight decay to apply to normalization parameters
**kwargs – keyword args passed to the schedulers

load(state: Dict[str, Any]) → None[source]¶

Resume from a trainer state

Parameters:: state (dict) – checkpoint dictionary

plot_recorder(beta: float = 0.95, **kwargs: Any) → None[source]¶

Display the results of the LR grid search

Parameters:

beta (float, optional) – smoothing factor
kwargs – keyword args of matplotlib.pyplot.show

save(output_file: str) → None[source]¶

Save a trainer checkpoint

Parameters:: output_file – destination file path

set_device(gpu: int | None = None) → None[source]¶

Move tensor objects to the target GPU

Parameters:: gpu – index of the target GPU device

to_cuda(x: Tensor, target: Tensor | List[Dict[str, Tensor]]) → Tuple[Tensor, Tensor | List[Dict[str, Tensor]]][source]¶: Move input and target to GPU

Image classification¶

class holocron.trainer.ClassificationTrainer(model: Module, train_loader: DataLoader, val_loader: DataLoader, criterion: Module, optimizer: Optimizer, gpu: int | None = None, output_file: str = './checkpoint.pth', amp: bool = False, skip_nan_loss: bool = False, nan_tolerance: int = 5, gradient_acc: int = 1, gradient_clip: float | None = None, on_epoch_end: Callable[[Dict[str, float]], Any] | None = None)[source]¶

Image classification trainer class.

Parameters:

model – model to train
train_loader – training loader
val_loader – validation loader
criterion – loss criterion
optimizer – parameter optimizer
gpu – index of the GPU to use
output_file – path where checkpoints will be saved
amp – whether to use automatic mixed precision
skip_nan_loss – whether the optimizer step should be skipped when the loss is NaN
nan_tolerance – number of consecutive batches with NaN loss before stopping the training
gradient_acc – number of batches to accumulate the gradient of before performing the update step
gradient_clip – the gradient clip value
on_epoch_end – callback triggered at the end of an epoch

evaluate() → Dict[str, float][source]¶

Evaluate the model on the validation set

Returns:: evaluation metrics
Return type:: dict

class holocron.trainer.BinaryClassificationTrainer(model: Module, train_loader: DataLoader, val_loader: DataLoader, criterion: Module, optimizer: Optimizer, gpu: int | None = None, output_file: str = './checkpoint.pth', amp: bool = False, skip_nan_loss: bool = False, nan_tolerance: int = 5, gradient_acc: int = 1, gradient_clip: float | None = None, on_epoch_end: Callable[[Dict[str, float]], Any] | None = None)[source]¶

Image binary classification trainer class.

Parameters:

model (torch.nn.Module) – model to train
train_loader (torch.utils.data.DataLoader) – training loader
val_loader (torch.utils.data.DataLoader) – validation loader
criterion (torch.nn.Module) – loss criterion
optimizer (torch.optim.Optimizer) – parameter optimizer
gpu (int, optional) – index of the GPU to use
output_file (str, optional) – path where checkpoints will be saved
amp (bool, optional) – whether to use automatic mixed precision

evaluate() → Dict[str, float][source]¶

Evaluate the model on the validation set

Returns:: evaluation metrics
Return type:: dict

Semantic segmentation¶

class holocron.trainer.SegmentationTrainer(*args: Any, num_classes: int = 10, **kwargs: Any)[source]¶

Semantic segmentation trainer class.

Parameters:

model – model to train
train_loader – training loader
val_loader – validation loader
criterion – loss criterion
optimizer – parameter optimizer
gpu – index of the GPU to use
output_file – path where checkpoints will be saved
amp – whether to use automatic mixed precision
skip_nan_loss – whether the optimizer step should be skipped when the loss is NaN
nan_tolerance – number of consecutive batches with NaN loss before stopping the training
gradient_acc – number of batches to accumulate the gradient of before performing the update step
gradient_clip – the gradient clip value
on_epoch_end – callback triggered at the end of an epoch

evaluate(ignore_index: int = 255) → Dict[str, float][source]¶

Evaluate the model on the validation set

Parameters:: ignore_index (int, optional) – index of the class to ignore in evaluation
Returns:: evaluation metrics
Return type:: dict

Object detection¶

class holocron.trainer.DetectionTrainer(model: Module, train_loader: DataLoader, val_loader: DataLoader, criterion: Module, optimizer: Optimizer, gpu: int | None = None, output_file: str = './checkpoint.pth', amp: bool = False, skip_nan_loss: bool = False, nan_tolerance: int = 5, gradient_acc: int = 1, gradient_clip: float | None = None, on_epoch_end: Callable[[Dict[str, float]], Any] | None = None)[source]¶

Object detection trainer class.

Parameters:

model – model to train
train_loader – training loader
val_loader – validation loader
criterion – loss criterion
optimizer – parameter optimizer
gpu – index of the GPU to use
output_file – path where checkpoints will be saved
amp – whether to use automatic mixed precision
skip_nan_loss – whether the optimizer step should be skipped when the loss is NaN
nan_tolerance – number of consecutive batches with NaN loss before stopping the training
gradient_acc – number of batches to accumulate the gradient of before performing the update step
gradient_clip – the gradient clip value
on_epoch_end – callback triggered at the end of an epoch

evaluate(iou_threshold: float = 0.5) → Dict[str, float | None][source]¶

Evaluate the model on the validation set.

Parameters:: iou_threshold (float, optional) – IoU threshold for pair assignment
Returns:: evaluation metrics
Return type:: dict

Miscellaneous¶

holocron.trainer.freeze_bn(mod: Module) → None[source]¶

Prevents parameter and stats from updating in Batchnorm layers that are frozen

>>> from holocron.models import rexnet1_0x
>>> from holocron.trainer.utils import freeze_bn
>>> model = rexnet1_0x()
>>> freeze_bn(model)

Parameters:: mod (torch.nn.Module) – model to train

holocron.trainer.freeze_model(model: Module, last_frozen_layer: str | None = None, frozen_bn_stat_update: bool = False) → None[source]¶

Freeze a specific range of model layers.

>>> from holocron.models import rexnet1_0x
>>> from holocron.trainer.utils import freeze_model
>>> model = rexnet1_0x()
>>> freeze_model(model)

Parameters:

model (torch.nn.Module) – model to train
last_frozen_layer (str, optional) – last layer to freeze. Assumes layers have been registered in forward order
frozen_bn_stat_update (bool, optional) – force stats update in BN layers that are frozen