1/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7 http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15
16#ifndef TENSORFLOW_CORE_KERNELS_REVERSE_SEQUENCE_OP_H_
17#define TENSORFLOW_CORE_KERNELS_REVERSE_SEQUENCE_OP_H_
18// Generator definition for ReverseSequenceOp, must be compilable by nvcc.
19
20#include "third_party/eigen3/unsupported/Eigen/CXX11/Tensor"
21#include "tensorflow/core/framework/tensor_types.h"
22#include "tensorflow/core/platform/types.h"
23
24namespace tensorflow {
25
26namespace generator {
27
28template <typename T, typename Tlen, size_t Dims>
29class ReverseGenerator {
30 public:
31 EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE ReverseGenerator(
32 typename TTypes<T, Dims>::ConstTensor input, int32_t batch_dim,
33 int32_t seq_dim, typename TTypes<Tlen>::ConstVec seq_lengths)
34 : input_(input),
35 batch_dim_(batch_dim),
36 seq_dim_(seq_dim),
37 seq_lengths_(seq_lengths) {}
38
39 EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE T
40 operator()(const Eigen::array<Eigen::DenseIndex, Dims>& coords) const {
41 Eigen::array<Eigen::DenseIndex, Dims> new_coords = coords;
42 if (coords[seq_dim_] < seq_lengths_(coords[batch_dim_])) {
43 new_coords[seq_dim_] =
44 seq_lengths_(coords[batch_dim_]) - coords[seq_dim_] - 1;
45 }
46
47 return input_(new_coords);
48 }
49
50 private:
51 typename TTypes<T, Dims>::ConstTensor input_;
52 int32 batch_dim_;
53 int32 seq_dim_;
54 typename TTypes<Tlen>::ConstVec seq_lengths_;
55};
56
57} // namespace generator
58
59namespace functor {
60
61template <typename Device, typename T, typename Tlen, size_t Dims>
62struct ReverseSequence {
63 EIGEN_ALWAYS_INLINE static void Compute(
64 const Device& d, typename TTypes<T, Dims>::ConstTensor input,
65 int32_t batch_dim, int32_t seq_dim,
66 typename TTypes<Tlen>::ConstVec seq_lengths,
67 typename TTypes<T, Dims>::Tensor output) {
68 generator::ReverseGenerator<T, Tlen, Dims> generator(input, batch_dim,
69 seq_dim, seq_lengths);
70 output.device(d) = input.generate(generator);
71 }
72};
73
74} // namespace functor
75
76} // namespace tensorflow
77
78#endif // TENSORFLOW_CORE_KERNELS_REVERSE_SEQUENCE_OP_H_
79