148 lines
4.0 KiB
Python
148 lines
4.0 KiB
Python
# Copyright 2019 The TensorFlow Authors. All Rights Reserved.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
# ==============================================================================
|
|
"""Keras backend config API."""
|
|
|
|
from tensorflow.python.util import dispatch
|
|
from tensorflow.python.util.tf_export import keras_export
|
|
|
|
# The type of float to use throughout a session.
|
|
_FLOATX = 'float32'
|
|
|
|
# Epsilon fuzz factor used throughout the codebase.
|
|
_EPSILON = 1e-7
|
|
|
|
# Default image data format, one of "channels_last", "channels_first".
|
|
_IMAGE_DATA_FORMAT = 'channels_last'
|
|
|
|
|
|
@keras_export('keras.backend.epsilon')
|
|
@dispatch.add_dispatch_support
|
|
def epsilon():
|
|
"""Returns the value of the fuzz factor used in numeric expressions.
|
|
|
|
Returns:
|
|
A float.
|
|
|
|
Example:
|
|
>>> tf.keras.backend.epsilon()
|
|
1e-07
|
|
"""
|
|
return _EPSILON
|
|
|
|
|
|
@keras_export('keras.backend.set_epsilon')
|
|
def set_epsilon(value):
|
|
"""Sets the value of the fuzz factor used in numeric expressions.
|
|
|
|
Args:
|
|
value: float. New value of epsilon.
|
|
|
|
Example:
|
|
>>> tf.keras.backend.epsilon()
|
|
1e-07
|
|
>>> tf.keras.backend.set_epsilon(1e-5)
|
|
>>> tf.keras.backend.epsilon()
|
|
1e-05
|
|
>>> tf.keras.backend.set_epsilon(1e-7)
|
|
"""
|
|
global _EPSILON
|
|
_EPSILON = value
|
|
|
|
|
|
@keras_export('keras.backend.floatx')
|
|
def floatx():
|
|
"""Returns the default float type, as a string.
|
|
|
|
E.g. `'float16'`, `'float32'`, `'float64'`.
|
|
|
|
Returns:
|
|
String, the current default float type.
|
|
|
|
Example:
|
|
>>> tf.keras.backend.floatx()
|
|
'float32'
|
|
"""
|
|
return _FLOATX
|
|
|
|
|
|
@keras_export('keras.backend.set_floatx')
|
|
def set_floatx(value):
|
|
"""Sets the default float type.
|
|
|
|
Note: It is not recommended to set this to float16 for training, as this will
|
|
likely cause numeric stability issues. Instead, mixed precision, which is
|
|
using a mix of float16 and float32, can be used by calling
|
|
`tf.keras.mixed_precision.set_global_policy('mixed_float16')`. See the
|
|
[mixed precision guide](
|
|
https://www.tensorflow.org/guide/keras/mixed_precision) for details.
|
|
|
|
Args:
|
|
value: String; `'float16'`, `'float32'`, or `'float64'`.
|
|
|
|
Example:
|
|
>>> tf.keras.backend.floatx()
|
|
'float32'
|
|
>>> tf.keras.backend.set_floatx('float64')
|
|
>>> tf.keras.backend.floatx()
|
|
'float64'
|
|
>>> tf.keras.backend.set_floatx('float32')
|
|
|
|
Raises:
|
|
ValueError: In case of invalid value.
|
|
"""
|
|
global _FLOATX
|
|
if value not in {'float16', 'float32', 'float64'}:
|
|
raise ValueError('Unknown floatx type: ' + str(value))
|
|
_FLOATX = str(value)
|
|
|
|
|
|
@keras_export('keras.backend.image_data_format')
|
|
@dispatch.add_dispatch_support
|
|
def image_data_format():
|
|
"""Returns the default image data format convention.
|
|
|
|
Returns:
|
|
A string, either `'channels_first'` or `'channels_last'`
|
|
|
|
Example:
|
|
>>> tf.keras.backend.image_data_format()
|
|
'channels_last'
|
|
"""
|
|
return _IMAGE_DATA_FORMAT
|
|
|
|
|
|
@keras_export('keras.backend.set_image_data_format')
|
|
def set_image_data_format(data_format):
|
|
"""Sets the value of the image data format convention.
|
|
|
|
Args:
|
|
data_format: string. `'channels_first'` or `'channels_last'`.
|
|
|
|
Example:
|
|
>>> tf.keras.backend.image_data_format()
|
|
'channels_last'
|
|
>>> tf.keras.backend.set_image_data_format('channels_first')
|
|
>>> tf.keras.backend.image_data_format()
|
|
'channels_first'
|
|
>>> tf.keras.backend.set_image_data_format('channels_last')
|
|
|
|
Raises:
|
|
ValueError: In case of invalid `data_format` value.
|
|
"""
|
|
global _IMAGE_DATA_FORMAT
|
|
if data_format not in {'channels_last', 'channels_first'}:
|
|
raise ValueError('Unknown data_format: ' + str(data_format))
|
|
_IMAGE_DATA_FORMAT = str(data_format)
|