226 lines
7.1 KiB
Python
226 lines
7.1 KiB
Python
# Copyright 2015 The TensorFlow 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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"""Contains layer utilities for input validation and format conversion."""
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from tensorflow.python.framework import smart_cond as smart_module
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from tensorflow.python.ops import cond
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from tensorflow.python.ops import variables
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def convert_data_format(data_format, ndim):
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if data_format == 'channels_last':
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if ndim == 3:
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return 'NWC'
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elif ndim == 4:
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return 'NHWC'
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elif ndim == 5:
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return 'NDHWC'
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else:
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raise ValueError(f'Input rank: {ndim} not supported. We only support '
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'input rank 3, 4 or 5.')
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elif data_format == 'channels_first':
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if ndim == 3:
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return 'NCW'
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elif ndim == 4:
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return 'NCHW'
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elif ndim == 5:
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return 'NCDHW'
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else:
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raise ValueError(f'Input rank: {ndim} not supported. We only support '
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'input rank 3, 4 or 5.')
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else:
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raise ValueError(f'Invalid data_format: {data_format}. We only support '
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'"channels_first" or "channels_last"')
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def normalize_tuple(value, n, name):
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"""Transforms a single integer or iterable of integers into an integer tuple.
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Args:
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value: The value to validate and convert. Could an int, or any iterable
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of ints.
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n: The size of the tuple to be returned.
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name: The name of the argument being validated, e.g. "strides" or
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"kernel_size". This is only used to format error messages.
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Returns:
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A tuple of n integers.
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Raises:
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ValueError: If something else than an int/long or iterable thereof was
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passed.
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"""
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if isinstance(value, int):
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return (value,) * n
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else:
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try:
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value_tuple = tuple(value)
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except TypeError:
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raise ValueError(f'Argument `{name}` must be a tuple of {str(n)} '
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f'integers. Received: {str(value)}')
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if len(value_tuple) != n:
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raise ValueError(f'Argument `{name}` must be a tuple of {str(n)} '
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f'integers. Received: {str(value)}')
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for single_value in value_tuple:
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try:
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int(single_value)
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except (ValueError, TypeError):
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raise ValueError(f'Argument `{name}` must be a tuple of {str(n)} '
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f'integers. Received: {str(value)} including element '
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f'{str(single_value)} of type '
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f'{str(type(single_value))}')
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return value_tuple
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def normalize_data_format(value):
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data_format = value.lower()
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if data_format not in {'channels_first', 'channels_last'}:
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raise ValueError('The `data_format` argument must be one of '
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'"channels_first", "channels_last". Received: '
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f'{str(value)}.')
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return data_format
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def normalize_padding(value):
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padding = value.lower()
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if padding not in {'valid', 'same'}:
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raise ValueError('The `padding` argument must be one of "valid", "same". '
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f'Received: {str(padding)}.')
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return padding
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def conv_output_length(input_length, filter_size, padding, stride, dilation=1):
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"""Determines output length of a convolution given input length.
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Args:
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input_length: integer.
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filter_size: integer.
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padding: one of "same", "valid", "full".
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stride: integer.
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dilation: dilation rate, integer.
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Returns:
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The output length (integer).
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"""
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if input_length is None:
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return None
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assert padding in {'same', 'valid', 'full'}
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dilated_filter_size = filter_size + (filter_size - 1) * (dilation - 1)
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if padding == 'same':
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output_length = input_length
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elif padding == 'valid':
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output_length = input_length - dilated_filter_size + 1
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elif padding == 'full':
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output_length = input_length + dilated_filter_size - 1
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return (output_length + stride - 1) // stride
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def conv_input_length(output_length, filter_size, padding, stride):
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"""Determines input length of a convolution given output length.
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Args:
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output_length: integer.
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filter_size: integer.
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padding: one of "same", "valid", "full".
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stride: integer.
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Returns:
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The input length (integer).
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"""
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if output_length is None:
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return None
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assert padding in {'same', 'valid', 'full'}
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if padding == 'same':
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pad = filter_size // 2
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elif padding == 'valid':
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pad = 0
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elif padding == 'full':
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pad = filter_size - 1
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return (output_length - 1) * stride - 2 * pad + filter_size
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def deconv_output_length(input_length, filter_size, padding, stride):
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"""Determines output length of a transposed convolution given input length.
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Args:
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input_length: integer.
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filter_size: integer.
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padding: one of "same", "valid", "full".
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stride: integer.
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Returns:
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The output length (integer).
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"""
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if input_length is None:
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return None
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input_length *= stride
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if padding == 'valid':
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input_length += max(filter_size - stride, 0)
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elif padding == 'full':
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input_length -= (stride + filter_size - 2)
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return input_length
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def smart_cond(pred, true_fn=None, false_fn=None, name=None):
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"""Return either `true_fn()` if predicate `pred` is true else `false_fn()`.
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If `pred` is a bool or has a constant value, we return either `true_fn()`
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or `false_fn()`, otherwise we use `tf.cond` to dynamically route to both.
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Args:
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pred: A scalar determining whether to return the result of `true_fn` or
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`false_fn`.
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true_fn: The callable to be performed if pred is true.
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false_fn: The callable to be performed if pred is false.
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name: Optional name prefix when using `tf.cond`.
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Returns:
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Tensors returned by the call to either `true_fn` or `false_fn`.
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Raises:
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TypeError: If `true_fn` or `false_fn` is not callable.
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"""
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if isinstance(pred, variables.Variable):
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return cond.cond(
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pred, true_fn=true_fn, false_fn=false_fn, name=name)
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return smart_module.smart_cond(
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pred, true_fn=true_fn, false_fn=false_fn, name=name)
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def constant_value(pred):
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"""Return the bool value for `pred`, or None if `pred` had a dynamic value.
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Args:
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pred: A scalar, either a Python bool or a TensorFlow boolean variable
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or tensor, or the Python integer 1 or 0.
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Returns:
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True or False if `pred` has a constant boolean value, None otherwise.
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Raises:
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TypeError: If `pred` is not a Variable, Tensor or bool, or Python
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integer 1 or 0.
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"""
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# Allow integer booleans.
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if isinstance(pred, int):
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if pred == 1:
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pred = True
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elif pred == 0:
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pred = False
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if isinstance(pred, variables.Variable):
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return None
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return smart_module.smart_constant_value(pred)
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