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https://github.com/zebrajr/pytorch.git
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fb22f76eb6
Summary: Based on #15331 . Review only the last commit. Fixes https://github.com/pytorch/pytorch/issues/14507. Pull Request resolved: https://github.com/pytorch/pytorch/pull/14669 Reviewed By: ezyang Differential Revision: D13528725 Pulled By: soumith fbshipit-source-id: f12f1ac1c4ff2a3ddd6877c0c096a5da3a1ffa3c
69 lines
2.6 KiB
Python
69 lines
2.6 KiB
Python
r""""Contains definitions of the methods used by the _DataLoaderIter workers to
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collate samples fetched from dataset into Tensor(s).
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These **needs** to be in global scope since Py2 doesn't support serializing
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static methods.
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"""
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import torch
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import re
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from torch._six import container_abcs, string_classes, int_classes
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_use_shared_memory = False
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r"""Whether to use shared memory in default_collate"""
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np_str_obj_array_pattern = re.compile(r'[SaUO]')
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error_msg_fmt = "batch must contain tensors, numbers, dicts or lists; found {}"
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numpy_type_map = {
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'float64': torch.DoubleTensor,
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'float32': torch.FloatTensor,
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'float16': torch.HalfTensor,
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'int64': torch.LongTensor,
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'int32': torch.IntTensor,
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'int16': torch.ShortTensor,
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'int8': torch.CharTensor,
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'uint8': torch.ByteTensor,
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}
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def default_collate(batch):
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r"""Puts each data field into a tensor with outer dimension batch size"""
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elem_type = type(batch[0])
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if isinstance(batch[0], torch.Tensor):
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out = None
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if _use_shared_memory:
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# If we're in a background process, concatenate directly into a
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# shared memory tensor to avoid an extra copy
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numel = sum([x.numel() for x in batch])
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storage = batch[0].storage()._new_shared(numel)
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out = batch[0].new(storage)
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return torch.stack(batch, 0, out=out)
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elif elem_type.__module__ == 'numpy' and elem_type.__name__ != 'str_' \
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and elem_type.__name__ != 'string_':
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elem = batch[0]
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if elem_type.__name__ == 'ndarray':
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# array of string classes and object
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if np_str_obj_array_pattern.search(elem.dtype.str) is not None:
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raise TypeError(error_msg_fmt.format(elem.dtype))
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return torch.stack([torch.from_numpy(b) for b in batch], 0)
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if elem.shape == (): # scalars
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py_type = float if elem.dtype.name.startswith('float') else int
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return numpy_type_map[elem.dtype.name](list(map(py_type, batch)))
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elif isinstance(batch[0], float):
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return torch.tensor(batch, dtype=torch.float64)
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elif isinstance(batch[0], int_classes):
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return torch.tensor(batch)
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elif isinstance(batch[0], string_classes):
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return batch
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elif isinstance(batch[0], container_abcs.Mapping):
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return {key: default_collate([d[key] for d in batch]) for key in batch[0]}
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elif isinstance(batch[0], container_abcs.Sequence):
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transposed = zip(*batch)
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return [default_collate(samples) for samples in transposed]
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raise TypeError((error_msg_fmt.format(type(batch[0]))))
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