composer.datasets.dataset_hparams#
Dataloader and Dataset Hyperparameter classes.
Hparams
These classes are used with yahp
for YAML
-based configuration.
Hyperparameters to initialize a |
- class composer.datasets.dataset_hparams.DataLoaderHparams(num_workers=8, prefetch_factor=2, persistent_workers=True, pin_memory=True, timeout=0.0)[source]#
Bases:
yahp.hparams.Hparams
Hyperparameters to initialize a
torch.utils.data.DataLoader
.- Parameters
num_workers (int, optional) โ Number of CPU workers to use per device to fetch data. Set to
0
to use the main training thread for dataloading. While zero workers can be useful for debugging, it should not be used for performance reasons. Default:8
.prefetch_factor (int, optional) โ Number of samples loaded in advance by each worker. For example, 2 means there will be a total of 2 * num_workers samples prefetched across all workers. If
num_workers = 0
, then theprefetch_factor
must be left at the default value. Default:2
.persistent_workers (bool) โ Whether to reuse dataloader workers across epochs. If
num_workers
is 0, then this field must beFalse
. Default:True
.pin_memory (bool, optional) โ Whether or not to copy Tensors into CUDA pinned memory before returning them. If
num_workers = 0
, then thepin_memory
must beFalse
. Default:True
.timeout (float) โ Timeout, in seconds, for collecting a batch from workers. Set to
0
for no timeout. Default:0
.
- initialize_object(dataset, *, batch_size, sampler, drop_last, collate_fn=None, worker_init_fn=None)[source]#
Create a dataloader.
- Parameters
dataset (Dataset) โ The dataset.
batch_size (int) โ The per-device batch size.
sampler (Sampler[int] | None) โ The sampler to use for the dataloader.
drop_last (bool) โ Whether to drop the last batch if the number of samples is not evenly divisible by the batch size.
collate_fn (callable, optional) โ Custom collate function. Default:
None
.worker_init_fn (callable, optional) โ Custom worker init function. Default:
None
.
- Returns
DataLoader โ The dataloader.
- class composer.datasets.dataset_hparams.DatasetHparams(drop_last=True, shuffle=True)[source]#
Bases:
yahp.hparams.Hparams
,abc.ABC
Abstract base class for hyperparameters to initialize a dataset.
- Parameters
- abstract initialize_object(batch_size, dataloader_hparams)[source]#
Creates a
DataLoader
orDataSpec
for this dataset.- Parameters
batch_size (int) โ The size of the batch the dataloader should yield. This batch size is device-specific and already incorporates the world size.
dataloader_hparams (DataLoaderHparams) โ The dataset-independent hparams for the dataloader.
- Returns
Iterable | DataSpec โ An iterable that yields batches, or if the dataset yields batches that need custom
processing, a :class:`~core.data_spec.DataSpec`.