# Copyright 2015 Google Inc. 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.

# ==============================================================================

"""## Hashing

String hashing ops take a string input tensor and map each element to an

integer.

@@string_to_hash_bucket

## Joining

String joining ops concatenate elements of input string tensors to produce a new

string tensor.

@@reduce_join

"""

from __future__ import absolute_import

from __future__ import division

from __future__ import print_function

import numpy as np

from tensorflow.python.framework import ops

from tensorflow.python.framework import tensor_shape

from tensorflow.python.framework import tensor_util

from tensorflow.python.ops import common_shapes

# pylint: disable=unused-import

from tensorflow.python.ops import gen_string_ops

# pylint: enable=unused-import

# go/tf-wildcard-import

# pylint: disable=wildcard-import

from tensorflow.python.ops.gen_string_ops import *

# pylint: enable=wildcard-import

ops.NoGradient("StringToHashBucket")

ops.NoGradient("ReduceJoin")

ops.RegisterShape("StringToHashBucket")(common_shapes.unchanged_shape)

@ops.RegisterShape("ReduceJoin")

def _ReduceJoinShape(op):

"""Shape function for the ReduceJoin op."""

input_shape = op.inputs[0].get_shape()

reduction_indices = np.ravel(tensor_util.constant_value(op.inputs[1]))

keep_dims = op.get_attr("keep_dims")

if input_shape.ndims is None:

return [tensor_shape.unknown_shape()]

if input_shape.ndims == 0:

raise ValueError("Input string tensor cannot be a scalar.")

true_indices = set()

for reduction_index in reduction_indices:

if reduction_index is None:

return [tensor_shape.unknown_shape()]

if (reduction_index < -input_shape.ndims or

reduction_index >= input_shape.ndims):

raise ValueError("Invalid reduction dimension %d for input with %d "

"dimensions" % (reduction_index, input_shape.ndims))

true_index = reduction_index % input_shape.ndims

if true_index in true_indices:

raise ValueError("Duplicate reduction index %d." % reduction_index)

if input_shape.dims[true_index] == 0:

raise ValueError("Cannot reduce dimension %d with size 0." %

reduction_index)

true_indices.add(true_index)

returned_dims = []

for i, dim in enumerate(input_shape.dims):

if i in true_indices:

if keep_dims:

returned_dims.append(1)

else:

returned_dims.append(dim)

return [tensor_shape.TensorShape(returned_dims)]