lbls = np.random.randint(0, 2, size=(10)) # Dataset of size 10 (train=8, valid=2)
is_valid = lambda i: i >= 8
dblock = DataBlock(blocks=[CategoryBlock],
getters=[lambda i: lbls[i]], splitter=FuncSplitter(is_valid))
dset = dblock.datasets(list(range(10)))
item_tfms = [ToTensor()]
wgts = range(8) # len(wgts) == 8
dls = dset.weighted_dataloaders(bs=1, wgts=wgts, after_item=item_tfms)Data Callbacks
Callbacks which work with a learner’s data
CollectDataCallback
CollectDataCallback (after_create=None, before_fit=None, before_epoch=None, before_train=None, before_batch=None, after_pred=None, after_loss=None, before_backward=None, after_cancel_backward=None, after_backward=None, before_step=None, after_cancel_step=None, after_step=None, after_cancel_batch=None, after_batch=None, after_cancel_train=None, after_train=None, before_validate=None, after_cancel_validate=None, after_validate=None, after_cancel_epoch=None, after_epoch=None, after_cancel_fit=None, after_fit=None)
Collect all batches, along with pred and loss, into self.data. Mainly for testing
WeightedDL
WeightedDL (dataset=None, bs=None, wgts=None, shuffle:bool=False, num_workers:int=None, verbose:bool=False, do_setup:bool=True, pin_memory=False, timeout=0, batch_size=None, drop_last=False, indexed=None, n=None, device=None, persistent_workers=False, pin_memory_device='', wif=None, before_iter=None, after_item=None, before_batch=None, after_batch=None, after_iter=None, create_batches=None, create_item=None, create_batch=None, retain=None, get_idxs=None, sample=None, shuffle_fn=None, do_batch=None)
Weighted dataloader where wgts is used for the training set only
Datasets.weighted_dataloaders
Datasets.weighted_dataloaders (wgts, bs=64, shuffle_train:bool=None, shuffle:bool=True, val_shuffle:bool=False, n:int=None, path:str|Path='.', dl_type:TfmdDL=None, dl_kwargs:list=None, device:torch.device=None, drop_last:bool=None, val_bs:int=None)
Create a weighted dataloader WeightedDL with wgts for the training set
| Type | Default | Details | |
|---|---|---|---|
| wgts | |||
| bs | int | 64 | Batch size |
| shuffle_train | bool | None | (Deprecated, use shuffle) Shuffle training DataLoader |
| shuffle | bool | True | Shuffle training DataLoader |
| val_shuffle | bool | False | Shuffle validation DataLoader |
| n | int | None | Size of Datasets used to create DataLoader |
| path | str | pathlib.Path | . | Path to put in DataLoaders |
| dl_type | TfmdDL | None | Type of DataLoader |
| dl_kwargs | list | None | List of kwargs to pass to individual DataLoaders |
| device | device | None | Device to put DataLoaders |
| drop_last | bool | None | Drop last incomplete batch, defaults to shuffle |
| val_bs | int | None | Validation batch size, defaults to bs |
dls.show_batch() # if len(wgts) != 8, this will fail"1
n = 160
dsets = Datasets(torch.arange(n).float())
dls = dsets.weighted_dataloaders(wgts=range(n), bs=16)
learn = synth_learner(data=dls, cbs=CollectDataCallback)learn.fit(1)
t = concat(*learn.collect_data.data.itemgot(0,0))
plt.hist(t.numpy());[0, nan, None, '00:00']

DataBlock.weighted_dataloaders
DataBlock.weighted_dataloaders (source, wgts, bs=64, verbose:bool=False, shuffle_train:bool=None, shuffle:bool=True, val_shuffle:bool=False, n:int=None, path:str|Path='.', dl_type:TfmdDL=None, dl_kwargs:list=None, device:torch.device=None, drop_last:bool=None, val_bs:int=None)
Create a weighted dataloader WeightedDL with wgts for the dataset
| Type | Default | Details | |
|---|---|---|---|
| source | |||
| wgts | |||
| bs | int | 64 | Batch size |
| verbose | bool | False | |
| shuffle_train | bool | None | (Deprecated, use shuffle) Shuffle training DataLoader |
| shuffle | bool | True | Shuffle training DataLoader |
| val_shuffle | bool | False | Shuffle validation DataLoader |
| n | int | None | Size of Datasets used to create DataLoader |
| path | str | pathlib.Path | . | Path to put in DataLoaders |
| dl_type | TfmdDL | None | Type of DataLoader |
| dl_kwargs | list | None | List of kwargs to pass to individual DataLoaders |
| device | device | None | Device to put DataLoaders |
| drop_last | bool | None | Drop last incomplete batch, defaults to shuffle |
| val_bs | int | None | Validation batch size, defaults to bs |
dls = dblock.weighted_dataloaders(list(range(10)), wgts, bs=1)
dls.show_batch()0
PartialDL
PartialDL (dataset=None, bs=None, partial_n=None, shuffle:bool=False, num_workers:int=None, verbose:bool=False, do_setup:bool=True, pin_memory=False, timeout=0, batch_size=None, drop_last=False, indexed=None, n=None, device=None, persistent_workers=False, pin_memory_device='', wif=None, before_iter=None, after_item=None, before_batch=None, after_batch=None, after_iter=None, create_batches=None, create_item=None, create_batch=None, retain=None, get_idxs=None, sample=None, shuffle_fn=None, do_batch=None)
Select randomly partial quantity of data at each epoch
FilteredBase.partial_dataloaders
FilteredBase.partial_dataloaders (partial_n, bs=64, shuffle_train:bool=None, shuffle:bool=True, val_shuffle:bool=False, n:int=None, path:str|Path='.', dl_type:TfmdDL=None, dl_kwargs:list=None, device:torch.device=None, drop_last:bool=None, val_bs:int=None)
Create a partial dataloader PartialDL for the training set
| Type | Default | Details | |
|---|---|---|---|
| partial_n | |||
| bs | int | 64 | Batch size |
| shuffle_train | bool | None | (Deprecated, use shuffle) Shuffle training DataLoader |
| shuffle | bool | True | Shuffle training DataLoader |
| val_shuffle | bool | False | Shuffle validation DataLoader |
| n | int | None | Size of Datasets used to create DataLoader |
| path | str | pathlib.Path | . | Path to put in DataLoaders |
| dl_type | TfmdDL | None | Type of DataLoader |
| dl_kwargs | list | None | List of kwargs to pass to individual DataLoaders |
| device | device | None | Device to put DataLoaders |
| drop_last | bool | None | Drop last incomplete batch, defaults to shuffle |
| val_bs | int | None | Validation batch size, defaults to bs |
dls = dsets.partial_dataloaders(partial_n=32, bs=16)assert len(dls[0])==2
for batch in dls[0]:
assert len(batch[0])==16