1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
# 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.
# ==============================================================================
"""Confusion matrix related utilities."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from tensorflow.python.framework import dtypes
from tensorflow.python.framework import ops
from tensorflow.python.framework import sparse_tensor
from tensorflow.python.ops import array_ops
from tensorflow.python.ops import check_ops
from tensorflow.python.ops import control_flow_ops
from tensorflow.python.ops import math_ops
from tensorflow.python.ops import sparse_ops
from tensorflow.python.util import deprecation
from tensorflow.python.util.tf_export import tf_export
def remove_squeezable_dimensions(
labels, predictions, expected_rank_diff=0, name=None):
"""Squeeze last dim if ranks differ from expected by exactly 1.
In the common case where we expect shapes to match, `expected_rank_diff`
defaults to 0, and we squeeze the last dimension of the larger rank if they
differ by 1.
But, for example, if `labels` contains class IDs and `predictions` contains 1
probability per class, we expect `predictions` to have 1 more dimension than
`labels`, so `expected_rank_diff` would be 1. In this case, we'd squeeze
`labels` if `rank(predictions) - rank(labels) == 0`, and
`predictions` if `rank(predictions) - rank(labels) == 2`.
This will use static shape if available. Otherwise, it will add graph
operations, which could result in a performance hit.
Args:
labels: Label values, a `Tensor` whose dimensions match `predictions`.
predictions: Predicted values, a `Tensor` of arbitrary dimensions.
expected_rank_diff: Expected result of `rank(predictions) - rank(labels)`.
name: Name of the op.
Returns:
Tuple of `labels` and `predictions`, possibly with last dim squeezed.
"""
with ops.name_scope(name, 'remove_squeezable_dimensions',
[labels, predictions]):
predictions = ops.convert_to_tensor(predictions)
labels = ops.convert_to_tensor(labels)
predictions_shape = predictions.get_shape()
predictions_rank = predictions_shape.ndims
labels_shape = labels.get_shape()
labels_rank = labels_shape.ndims
if (labels_rank is not None) and (predictions_rank is not None):
# Use static rank.
rank_diff = predictions_rank - labels_rank
if rank_diff == expected_rank_diff + 1:
predictions = array_ops.squeeze(predictions, [-1])
elif rank_diff == expected_rank_diff - 1:
labels = array_ops.squeeze(labels, [-1])
return labels, predictions
# Use dynamic rank.
rank_diff = array_ops.rank(predictions) - array_ops.rank(labels)
if (predictions_rank is None) or (
predictions_shape.dims[-1].is_compatible_with(1)):
predictions = control_flow_ops.cond(
math_ops.equal(expected_rank_diff + 1, rank_diff),
lambda: array_ops.squeeze(predictions, [-1]),
lambda: predictions)
if (labels_rank is None) or (
labels_shape.dims[-1].is_compatible_with(1)):
labels = control_flow_ops.cond(
math_ops.equal(expected_rank_diff - 1, rank_diff),
lambda: array_ops.squeeze(labels, [-1]),
lambda: labels)
return labels, predictions
@tf_export('train.confusion_matrix', 'confusion_matrix')
@deprecation.deprecated_endpoints('confusion_matrix')
def confusion_matrix(labels, predictions, num_classes=None, dtype=dtypes.int32,
name=None, weights=None):
"""Computes the confusion matrix from predictions and labels.
The matrix columns represent the prediction labels and the rows represent the
real labels. The confusion matrix is always a 2-D array of shape `[n, n]`,
where `n` is the number of valid labels for a given classification task. Both
prediction and labels must be 1-D arrays of the same shape in order for this
function to work.
If `num_classes` is `None`, then `num_classes` will be set to one plus the
maximum value in either predictions or labels. Class labels are expected to
start at 0. For example, if `num_classes` is 3, then the possible labels
would be `[0, 1, 2]`.
If `weights` is not `None`, then each prediction contributes its
corresponding weight to the total value of the confusion matrix cell.
For example:
```python
tf.confusion_matrix([1, 2, 4], [2, 2, 4]) ==>
[[0 0 0 0 0]
[0 0 1 0 0]
[0 0 1 0 0]
[0 0 0 0 0]
[0 0 0 0 1]]
```
Note that the possible labels are assumed to be `[0, 1, 2, 3, 4]`,
resulting in a 5x5 confusion matrix.
Args:
labels: 1-D `Tensor` of real labels for the classification task.
predictions: 1-D `Tensor` of predictions for a given classification.
num_classes: The possible number of labels the classification task can
have. If this value is not provided, it will be calculated
using both predictions and labels array.
dtype: Data type of the confusion matrix.
name: Scope name.
weights: An optional `Tensor` whose shape matches `predictions`.
Returns:
A `Tensor` of type `dtype` with shape `[n, n]` representing the confusion
matrix, where `n` is the number of possible labels in the classification
task.
Raises:
ValueError: If both predictions and labels are not 1-D vectors and have
mismatched shapes, or if `weights` is not `None` and its shape doesn't
match `predictions`.
"""
with ops.name_scope(name, 'confusion_matrix',
(predictions, labels, num_classes, weights)) as name:
labels, predictions = remove_squeezable_dimensions(
ops.convert_to_tensor(labels, name='labels'),
ops.convert_to_tensor(
predictions, name='predictions'))
predictions = math_ops.cast(predictions, dtypes.int64)
labels = math_ops.cast(labels, dtypes.int64)
# Sanity checks - underflow or overflow can cause memory corruption.
labels = control_flow_ops.with_dependencies(
[check_ops.assert_non_negative(
labels, message='`labels` contains negative values')],
labels)
predictions = control_flow_ops.with_dependencies(
[check_ops.assert_non_negative(
predictions, message='`predictions` contains negative values')],
predictions)
if num_classes is None:
num_classes = math_ops.maximum(math_ops.reduce_max(predictions),
math_ops.reduce_max(labels)) + 1
else:
num_classes_int64 = math_ops.cast(num_classes, dtypes.int64)
labels = control_flow_ops.with_dependencies(
[check_ops.assert_less(
labels, num_classes_int64, message='`labels` out of bound')],
labels)
predictions = control_flow_ops.with_dependencies(
[check_ops.assert_less(
predictions, num_classes_int64,
message='`predictions` out of bound')],
predictions)
if weights is not None:
predictions.get_shape().assert_is_compatible_with(weights.get_shape())
weights = math_ops.cast(weights, dtype)
shape = array_ops.stack([num_classes, num_classes])
indices = array_ops.stack([labels, predictions], axis=1)
values = (array_ops.ones_like(predictions, dtype)
if weights is None else weights)
cm_sparse = sparse_tensor.SparseTensor(
indices=indices, values=values, dense_shape=math_ops.to_int64(shape))
zero_matrix = array_ops.zeros(math_ops.to_int32(shape), dtype)
return sparse_ops.sparse_add(zero_matrix, cm_sparse)
|
