tesseract/lstm/parallel.h

88 lines
3.3 KiB
C++

///////////////////////////////////////////////////////////////////////
// File: parallel.h
// Description: Runs networks in parallel on the same input.
// Author: Ray Smith
// Created: Thu May 02 08:02:06 PST 2013
//
// (C) Copyright 2013, Google Inc.
// 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.
///////////////////////////////////////////////////////////////////////
#ifndef TESSERACT_LSTM_PARALLEL_H_
#define TESSERACT_LSTM_PARALLEL_H_
#include "plumbing.h"
namespace tesseract {
// Runs multiple networks in parallel, interlacing their outputs.
class Parallel : public Plumbing {
public:
// ni_ and no_ will be set by AddToStack.
Parallel(const STRING& name, NetworkType type);
virtual ~Parallel();
// Returns the shape output from the network given an input shape (which may
// be partially unknown ie zero).
virtual StaticShape OutputShape(const StaticShape& input_shape) const;
virtual STRING spec() const {
STRING spec;
if (type_ == NT_PAR_2D_LSTM) {
// We have 4 LSTMs operating in parallel here, so the size of each is
// the number of outputs/4.
spec.add_str_int("L2xy", no_ / 4);
} else if (type_ == NT_PAR_RL_LSTM) {
// We have 2 LSTMs operating in parallel here, so the size of each is
// the number of outputs/2.
if (stack_[0]->type() == NT_LSTM_SUMMARY)
spec.add_str_int("Lbxs", no_ / 2);
else
spec.add_str_int("Lbx", no_ / 2);
} else {
if (type_ == NT_REPLICATED) {
spec.add_str_int("R", stack_.size());
spec += "(";
spec += stack_[0]->spec();
} else {
spec = "(";
for (int i = 0; i < stack_.size(); ++i) spec += stack_[i]->spec();
}
spec += ")";
}
return spec;
}
// Runs forward propagation of activations on the input line.
// See Network for a detailed discussion of the arguments.
virtual void Forward(bool debug, const NetworkIO& input,
const TransposedArray* input_transpose,
NetworkScratch* scratch, NetworkIO* output);
// Runs backward propagation of errors on the deltas line.
// See Network for a detailed discussion of the arguments.
virtual bool Backward(bool debug, const NetworkIO& fwd_deltas,
NetworkScratch* scratch,
NetworkIO* back_deltas);
private:
// If *this is a NT_REPLICATED, then it feeds a replicated network with
// identical inputs, and it would be extremely wasteful for them to each
// calculate and store the same transpose of the inputs, so Parallel does it
// and passes a pointer to the replicated network, allowing it to use the
// transpose on the next call to Backward.
TransposedArray transposed_input_;
};
} // namespace tesseract.
#endif // TESSERACT_LSTM_PARALLEL_H_