tesseract v5.3.3.20231005
parallel.h
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1
2// File: parallel.h
3// Description: Runs networks in parallel on the same input.
4// Author: Ray Smith
5//
6// (C) Copyright 2013, Google Inc.
7// Licensed under the Apache License, Version 2.0 (the "License");
8// you may not use this file except in compliance with the License.
9// You may obtain a copy of the License at
10// http://www.apache.org/licenses/LICENSE-2.0
11// Unless required by applicable law or agreed to in writing, software
12// distributed under the License is distributed on an "AS IS" BASIS,
13// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14// See the License for the specific language governing permissions and
15// limitations under the License.
17
18#ifndef TESSERACT_LSTM_PARALLEL_H_
19#define TESSERACT_LSTM_PARALLEL_H_
20
21#include "plumbing.h"
22
23namespace tesseract {
24
25// Runs multiple networks in parallel, interlacing their outputs.
26class Parallel : public Plumbing {
27public:
28 // ni_ and no_ will be set by AddToStack.
30 Parallel(const char *name, NetworkType type);
31
32 // Returns the shape output from the network given an input shape (which may
33 // be partially unknown ie zero).
34 StaticShape OutputShape(const StaticShape &input_shape) const override;
35
36 std::string spec() const override {
37 std::string spec;
38 if (type_ == NT_PAR_2D_LSTM) {
39 // We have 4 LSTMs operating in parallel here, so the size of each is
40 // the number of outputs/4.
41 spec += "L2xy" + std::to_string(no_ / 4);
42 } else if (type_ == NT_PAR_RL_LSTM) {
43 // We have 2 LSTMs operating in parallel here, so the size of each is
44 // the number of outputs/2.
45 if (stack_[0]->type() == NT_LSTM_SUMMARY) {
46 spec += "Lbxs" + std::to_string(no_ / 2);
47 } else {
48 spec += "Lbx" + std::to_string(no_ / 2);
49 }
50 } else {
51 if (type_ == NT_REPLICATED) {
52 spec += "R" + std::to_string(stack_.size()) + "(" + stack_[0]->spec();
53 } else {
54 for (auto &it : stack_) {
55 spec += it->spec();
56 }
57 }
58 spec += ")";
59 }
60 return spec;
61 }
62
63 // Runs forward propagation of activations on the input line.
64 // See Network for a detailed discussion of the arguments.
65 void Forward(bool debug, const NetworkIO &input, const TransposedArray *input_transpose,
66 NetworkScratch *scratch, NetworkIO *output) override;
67
68 // Runs backward propagation of errors on the deltas line.
69 // See Network for a detailed discussion of the arguments.
70 bool Backward(bool debug, const NetworkIO &fwd_deltas, NetworkScratch *scratch,
71 NetworkIO *back_deltas) override;
72
73private:
74 // If *this is a NT_REPLICATED, then it feeds a replicated network with
75 // identical inputs, and it would be extremely wasteful for them to each
76 // calculate and store the same transpose of the inputs, so Parallel does it
77 // and passes a pointer to the replicated network, allowing it to use the
78 // transpose on the next call to Backward.
79 TransposedArray transposed_input_;
80};
81
82} // namespace tesseract.
83
84#endif // TESSERACT_LSTM_PARALLEL_H_
NetworkType
Definition: network.h:41
@ NT_PAR_2D_LSTM
Definition: network.h:51
@ NT_LSTM_SUMMARY
Definition: network.h:59
@ NT_PAR_RL_LSTM
Definition: network.h:49
@ NT_REPLICATED
Definition: network.h:48
NetworkType type_
Definition: network.h:300
const std::string & name() const
Definition: network.h:140
NetworkType type() const
Definition: network.h:110
void Forward(bool debug, const NetworkIO &input, const TransposedArray *input_transpose, NetworkScratch *scratch, NetworkIO *output) override
Definition: parallel.cpp:52
bool Backward(bool debug, const NetworkIO &fwd_deltas, NetworkScratch *scratch, NetworkIO *back_deltas) override
Definition: parallel.cpp:113
TESS_API Parallel(const char *name, NetworkType type)
Definition: parallel.cpp:34
std::string spec() const override
Definition: parallel.h:36
StaticShape OutputShape(const StaticShape &input_shape) const override
Definition: parallel.cpp:40
std::vector< Network * > stack_
Definition: plumbing.h:147
#define TESS_API
Definition: export.h:32