tesseract/lstm/maxpool.cpp

88 lines
3.1 KiB
C++

///////////////////////////////////////////////////////////////////////
// File: maxpool.h
// Description: Standard Max-Pooling layer.
// Author: Ray Smith
// Created: Tue Mar 18 16:28:18 PST 2014
//
// (C) Copyright 2014, 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.
///////////////////////////////////////////////////////////////////////
#include "maxpool.h"
#include "tprintf.h"
namespace tesseract {
Maxpool::Maxpool(const STRING& name, int ni, int x_scale, int y_scale)
: Reconfig(name, ni, x_scale, y_scale) {
type_ = NT_MAXPOOL;
no_ = ni;
}
Maxpool::~Maxpool() {
}
// Reads from the given file. Returns false in case of error.
// If swap is true, assumes a big/little-endian swap is needed.
bool Maxpool::DeSerialize(bool swap, TFile* fp) {
bool result = Reconfig::DeSerialize(swap, fp);
no_ = ni_;
return result;
}
// Runs forward propagation of activations on the input line.
// See NetworkCpp for a detailed discussion of the arguments.
void Maxpool::Forward(bool debug, const NetworkIO& input,
const TransposedArray* input_transpose,
NetworkScratch* scratch, NetworkIO* output) {
output->ResizeScaled(input, x_scale_, y_scale_, no_);
maxes_.ResizeNoInit(output->Width(), ni_);
back_map_ = input.stride_map();
StrideMap::Index dest_index(output->stride_map());
do {
int out_t = dest_index.t();
StrideMap::Index src_index(input.stride_map(), dest_index.index(FD_BATCH),
dest_index.index(FD_HEIGHT) * y_scale_,
dest_index.index(FD_WIDTH) * x_scale_);
// Find the max input out of x_scale_ groups of y_scale_ inputs.
// Do it independently for each input dimension.
int* max_line = maxes_[out_t];
int in_t = src_index.t();
output->CopyTimeStepFrom(out_t, input, in_t);
for (int i = 0; i < ni_; ++i) {
max_line[i] = in_t;
}
for (int x = 0; x < x_scale_; ++x) {
for (int y = 0; y < y_scale_; ++y) {
StrideMap::Index src_xy(src_index);
if (src_xy.AddOffset(x, FD_WIDTH) && src_xy.AddOffset(y, FD_HEIGHT)) {
output->MaxpoolTimeStep(out_t, input, src_xy.t(), max_line);
}
}
}
} while (dest_index.Increment());
}
// Runs backward propagation of errors on the deltas line.
// See NetworkCpp for a detailed discussion of the arguments.
bool Maxpool::Backward(bool debug, const NetworkIO& fwd_deltas,
NetworkScratch* scratch,
NetworkIO* back_deltas) {
back_deltas->ResizeToMap(fwd_deltas.int_mode(), back_map_, ni_);
back_deltas->MaxpoolBackward(fwd_deltas, maxes_);
return true;
}
} // namespace tesseract.