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75 lines
2.5 KiB
75 lines
2.5 KiB
# Copyright (c) 2016 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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"""
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At training and testing time, PaddlePaddle programs need to read data. To ease
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the users' work to write data reading code, we define that
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- A *reader* is a function that reads data (from file, network, random number
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generator, etc) and yields data items.
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- A *reader creator* is a function that returns a reader function.
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- A *reader decorator* is a function, which accepts one or more readers, and
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returns a reader.
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- A *batch reader* is a function that reads data (from *reader*, file, network,
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random number generator, etc) and yields a batch of data items.
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#####################
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Data Reader Interface
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#####################
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Indeed, *data reader* doesn't have to be a function that reads and yields data
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items. It can be any function with no parameter that creates a iterable
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(anything can be used in :code:`for x in iterable`)\:
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.. code-block:: python
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iterable = data_reader()
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Element produced from the iterable should be a **single** entry of data,
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**not** a mini batch. That entry of data could be a single item, or a tuple of
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items.
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Item should be of `supported type <http://www.paddlepaddle.org/doc/ui/data_provider
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/pydataprovider2.html?highlight=dense_vector#input-types>`_ (e.g., numpy 1d
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array of float32, int, list of int)
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An example implementation for single item data reader creator:
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.. code-block:: python
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def reader_creator_random_image(width, height):
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def reader():
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while True:
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yield numpy.random.uniform(-1, 1, size=width*height)
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return reader
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An example implementation for multiple item data reader creator:
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.. code-block:: python
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def reader_creator_random_image_and_label(width, height, label):
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def reader():
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while True:
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yield numpy.random.uniform(-1, 1, size=width*height), label
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return reader
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TODO(yuyang18): Should we add whole design doc here?
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"""
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import decorator
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from decorator import *
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import creator
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__all__ = decorator.__all__ + ['creator']
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