94 lines
3.0 KiB
Python
94 lines
3.0 KiB
Python
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# 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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"""Layer that subtracts two inputs."""
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from keras.layers.merging.base_merge import _Merge
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from keras.utils import tf_utils
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# isort: off
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from tensorflow.python.util.tf_export import keras_export
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@keras_export("keras.layers.Subtract")
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class Subtract(_Merge):
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"""Layer that subtracts two inputs.
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It takes as input a list of tensors of size 2, both of the same shape, and
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returns a single tensor, (inputs[0] - inputs[1]), also of the same shape.
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Examples:
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```python
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import keras
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input1 = keras.layers.Input(shape=(16,))
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x1 = keras.layers.Dense(8, activation='relu')(input1)
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input2 = keras.layers.Input(shape=(32,))
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x2 = keras.layers.Dense(8, activation='relu')(input2)
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# Equivalent to subtracted = keras.layers.subtract([x1, x2])
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subtracted = keras.layers.Subtract()([x1, x2])
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out = keras.layers.Dense(4)(subtracted)
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model = keras.models.Model(inputs=[input1, input2], outputs=out)
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```
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"""
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@tf_utils.shape_type_conversion
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def build(self, input_shape):
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super().build(input_shape)
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if len(input_shape) != 2:
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raise ValueError(
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"A `Subtract` layer should be called on exactly 2 inputs. "
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f"Received: input_shape={input_shape}"
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)
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def _merge_function(self, inputs):
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if len(inputs) != 2:
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raise ValueError(
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"A `Subtract` layer should be called on exactly 2 inputs. "
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f"Received: inputs={inputs}"
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)
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return inputs[0] - inputs[1]
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@keras_export("keras.layers.subtract")
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def subtract(inputs, **kwargs):
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"""Functional interface to the `Subtract` layer.
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Args:
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inputs: A list of input tensors (exactly 2).
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**kwargs: Standard layer keyword arguments.
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Returns:
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A tensor, the difference of the inputs.
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Examples:
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```python
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import keras
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input1 = keras.layers.Input(shape=(16,))
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x1 = keras.layers.Dense(8, activation='relu')(input1)
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input2 = keras.layers.Input(shape=(32,))
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x2 = keras.layers.Dense(8, activation='relu')(input2)
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subtracted = keras.layers.subtract([x1, x2])
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out = keras.layers.Dense(4)(subtracted)
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model = keras.models.Model(inputs=[input1, input2], outputs=out)
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```
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"""
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return Subtract(**kwargs)(inputs)
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