/
histogram_ops.py
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/
histogram_ops.py
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# Copyright 2015 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.
# ==============================================================================
# pylint: disable=g-short-docstring-punctuation
"""Histograms.
"""
from tensorflow.python.framework import dtypes
from tensorflow.python.framework import ops
from tensorflow.python.ops import array_ops
from tensorflow.python.ops import clip_ops
from tensorflow.python.ops import control_flow_ops
from tensorflow.python.ops import gen_math_ops
from tensorflow.python.ops import math_ops
from tensorflow.python.util import dispatch
from tensorflow.python.util.tf_export import tf_export
@tf_export('histogram_fixed_width_bins')
@dispatch.add_dispatch_support
def histogram_fixed_width_bins(values,
value_range,
nbins=100,
dtype=dtypes.int32,
name=None):
"""Bins the given values for use in a histogram.
Given the tensor `values`, this operation returns a rank 1 `Tensor`
representing the indices of a histogram into which each element
of `values` would be binned. The bins are equal width and
determined by the arguments `value_range` and `nbins`.
Args:
values: Numeric `Tensor`.
value_range: Shape [2] `Tensor` of same `dtype` as `values`.
values <= value_range[0] will be mapped to hist[0],
values >= value_range[1] will be mapped to hist[-1].
nbins: Scalar `int32 Tensor`. Number of histogram bins.
dtype: dtype for returned histogram.
name: A name for this operation (defaults to 'histogram_fixed_width').
Returns:
A `Tensor` holding the indices of the binned values whose shape matches
`values`.
Raises:
TypeError: If any unsupported dtype is provided.
tf.errors.InvalidArgumentError: If value_range does not
satisfy value_range[0] < value_range[1].
Examples:
>>> # Bins will be: (-inf, 1), [1, 2), [2, 3), [3, 4), [4, inf)
...
>>> nbins = 5
>>> value_range = [0.0, 5.0]
>>> new_values = [-1.0, 0.0, 1.5, 2.0, 5.0, 15]
>>> indices = tf.histogram_fixed_width_bins(new_values, value_range, nbins=5)
>>> indices.numpy()
array([0, 0, 1, 2, 4, 4], dtype=int32)
"""
with ops.name_scope(name, 'histogram_fixed_width_bins',
[values, value_range, nbins]):
values = ops.convert_to_tensor(values, name='values')
shape = array_ops.shape(values)
values = array_ops.reshape(values, [-1])
value_range = ops.convert_to_tensor(value_range, name='value_range')
nbins = ops.convert_to_tensor(nbins, dtype=dtypes.int32, name='nbins')
check = control_flow_ops.Assert(
math_ops.greater(nbins, 0), ['nbins %s must > 0' % nbins])
nbins = control_flow_ops.with_dependencies([check], nbins)
nbins_float = math_ops.cast(nbins, values.dtype)
# Map tensor values that fall within value_range to [0, 1].
scaled_values = math_ops.truediv(
values - value_range[0],
value_range[1] - value_range[0],
name='scaled_values')
# map tensor values within the open interval value_range to {0,.., nbins-1},
# values outside the open interval will be zero or less, or nbins or more.
indices = math_ops.floor(nbins_float * scaled_values, name='indices')
# Clip edge cases (e.g. value = value_range[1]) or "outliers."
indices = math_ops.cast(
clip_ops.clip_by_value(indices, 0, nbins_float - 1), dtypes.int32)
return array_ops.reshape(indices, shape)
@tf_export('histogram_fixed_width')
@dispatch.add_dispatch_support
def histogram_fixed_width(values,
value_range,
nbins=100,
dtype=dtypes.int32,
name=None):
"""Return histogram of values.
Given the tensor `values`, this operation returns a rank 1 histogram counting
the number of entries in `values` that fell into every bin. The bins are
equal width and determined by the arguments `value_range` and `nbins`.
Args:
values: Numeric `Tensor`.
value_range: Shape [2] `Tensor` of same `dtype` as `values`.
values <= value_range[0] will be mapped to hist[0],
values >= value_range[1] will be mapped to hist[-1].
nbins: Scalar `int32 Tensor`. Number of histogram bins.
dtype: dtype for returned histogram.
name: A name for this operation (defaults to 'histogram_fixed_width').
Returns:
A 1-D `Tensor` holding histogram of values.
Raises:
TypeError: If any unsupported dtype is provided.
tf.errors.InvalidArgumentError: If value_range does not
satisfy value_range[0] < value_range[1].
Examples:
>>> # Bins will be: (-inf, 1), [1, 2), [2, 3), [3, 4), [4, inf)
...
>>> nbins = 5
>>> value_range = [0.0, 5.0]
>>> new_values = [-1.0, 0.0, 1.5, 2.0, 5.0, 15]
>>> hist = tf.histogram_fixed_width(new_values, value_range, nbins=5)
>>> hist.numpy()
array([2, 1, 1, 0, 2], dtype=int32)
"""
with ops.name_scope(name, 'histogram_fixed_width',
[values, value_range, nbins]) as name:
# pylint: disable=protected-access
return gen_math_ops._histogram_fixed_width(
values, value_range, nbins, dtype=dtype, name=name)
# pylint: enable=protected-access