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67 lines
2.4 KiB
67 lines
2.4 KiB
# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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class _DatasetFetcher(object):
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def __init__(self, dataset, auto_collate_batch, collate_fn, drop_last):
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self.dataset = dataset
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self.auto_collate_batch = auto_collate_batch
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self.collate_fn = collate_fn
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self.drop_last = drop_last
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def fetch(self, batch_indices):
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raise NotImplementedError("'fetch' not implement for class {}".format(
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self.__class__.__name__))
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class _IterableDatasetFetcher(_DatasetFetcher):
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def __init__(self, dataset, auto_collate_batch, collate_fn, drop_last):
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super(_IterableDatasetFetcher, self).__init__(dataset, auto_collate_batch,
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collate_fn, drop_last)
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self.dataset_iter = iter(dataset)
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def fetch(self, batch_indices):
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if self.auto_collate_batch:
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data = []
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for _ in batch_indices:
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try:
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data.append(next(self.dataset_iter))
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except StopIteration:
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break
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if len(data) == 0 or (self.drop_last and
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len(data) < len(batch_indices)):
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raise StopIteration
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else:
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data = next(self.dataset_iter)
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if self.collate_fn:
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data = self.collate_fn(data)
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return data
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class _MapDatasetFetcher(_DatasetFetcher):
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def __init__(self, dataset, auto_collate_batch, collate_fn, drop_last):
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super(_MapDatasetFetcher, self).__init__(dataset, auto_collate_batch, collate_fn, drop_last)
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def fetch(self, batch_indices):
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if self.auto_collate_batch:
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data = [self.dataset[idx] for idx in batch_indices]
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else:
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data = self.dataset[batch_indices]
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if self.collate_fn:
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data = self.collate_fn(data)
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return data
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