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67 lines
2.6 KiB
67 lines
2.6 KiB
# Copyright 2017 Paul Balanca. 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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"""TF Extended: additional math functions. |
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""" |
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import tensorflow as tf |
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from tensorflow.python.ops import array_ops |
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from tensorflow.python.ops import math_ops |
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from tensorflow.python.framework import dtypes |
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from tensorflow.python.framework import ops |
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def safe_divide(numerator, denominator, name): |
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"""Divides two values, returning 0 if the denominator is <= 0. |
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Args: |
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numerator: A real `Tensor`. |
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denominator: A real `Tensor`, with dtype matching `numerator`. |
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name: Name for the returned op. |
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Returns: |
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0 if `denominator` <= 0, else `numerator` / `denominator` |
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""" |
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return tf.where( |
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math_ops.greater(denominator, 0), |
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math_ops.divide(numerator, denominator), |
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tf.zeros_like(numerator), |
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name=name) |
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def cummax(x, reverse=False, name=None): |
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"""Compute the cumulative maximum of the tensor `x` along `axis`. This |
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operation is similar to the more classic `cumsum`. Only support 1D Tensor |
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for now. |
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Args: |
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x: A `Tensor`. Must be one of the following types: `float32`, `float64`, |
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`int64`, `int32`, `uint8`, `uint16`, `int16`, `int8`, `complex64`, |
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`complex128`, `qint8`, `quint8`, `qint32`, `half`. |
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axis: A `Tensor` of type `int32` (default: 0). |
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reverse: A `bool` (default: False). |
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name: A name for the operation (optional). |
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Returns: |
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A `Tensor`. Has the same type as `x`. |
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""" |
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with ops.name_scope(name, "Cummax", [x]) as name: |
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x = ops.convert_to_tensor(x, name="x") |
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# Not very optimal: should directly integrate reverse into tf.scan. |
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if reverse: |
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x = tf.reverse(x, axis=[0]) |
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# 'Accumlating' maximum: ensure it is always increasing. |
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cmax = tf.scan(lambda a, y: tf.maximum(a, y), x, |
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initializer=None, parallel_iterations=1, |
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back_prop=False, swap_memory=False) |
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if reverse: |
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cmax = tf.reverse(cmax, axis=[0]) |
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return cmax
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