tesseract/lstm/series.cpp

208 lines
7.9 KiB
C++

///////////////////////////////////////////////////////////////////////
// File: series.cpp
// Description: Runs networks in series on the same input.
// Author: Ray Smith
// Created: Thu May 02 08:26:06 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.
///////////////////////////////////////////////////////////////////////
#include "series.h"
#include "fullyconnected.h"
#include "networkscratch.h"
#include "scrollview.h"
#include "tprintf.h"
namespace tesseract {
// ni_ and no_ will be set by AddToStack.
Series::Series(const STRING& name) : Plumbing(name) {
type_ = NT_SERIES;
}
Series::~Series() {
}
// Returns the shape output from the network given an input shape (which may
// be partially unknown ie zero).
StaticShape Series::OutputShape(const StaticShape& input_shape) const {
StaticShape result(input_shape);
int stack_size = stack_.size();
for (int i = 0; i < stack_size; ++i) {
result = stack_[i]->OutputShape(result);
}
return result;
}
// Sets up the network for training. Initializes weights using weights of
// scale `range` picked according to the random number generator `randomizer`.
// Note that series has its own implementation just for debug purposes.
int Series::InitWeights(float range, TRand* randomizer) {
num_weights_ = 0;
tprintf("Num outputs,weights in Series:\n");
for (int i = 0; i < stack_.size(); ++i) {
int weights = stack_[i]->InitWeights(range, randomizer);
tprintf(" %s:%d, %d\n",
stack_[i]->spec().string(), stack_[i]->NumOutputs(), weights);
num_weights_ += weights;
}
tprintf("Total weights = %d\n", num_weights_);
return num_weights_;
}
// Changes the number of outputs to the size of the given code_map, copying
// the old weight matrix entries for each output from code_map[output] where
// non-negative, and uses the mean (over all outputs) of the existing weights
// for all outputs with negative code_map entries. Returns the new number of
// weights. Only operates on Softmax layers with old_no outputs.
int Series::RemapOutputs(int old_no, const std::vector<int>& code_map) {
num_weights_ = 0;
tprintf("Num (Extended) outputs,weights in Series:\n");
for (int i = 0; i < stack_.size(); ++i) {
int weights = stack_[i]->RemapOutputs(old_no, code_map);
tprintf(" %s:%d, %d\n", stack_[i]->spec().string(),
stack_[i]->NumOutputs(), weights);
num_weights_ += weights;
}
tprintf("Total weights = %d\n", num_weights_);
no_ = stack_.back()->NumOutputs();
return num_weights_;
}
// Sets needs_to_backprop_ to needs_backprop and returns true if
// needs_backprop || any weights in this network so the next layer forward
// can be told to produce backprop for this layer if needed.
bool Series::SetupNeedsBackprop(bool needs_backprop) {
needs_to_backprop_ = needs_backprop;
for (int i = 0; i < stack_.size(); ++i)
needs_backprop = stack_[i]->SetupNeedsBackprop(needs_backprop);
return needs_backprop;
}
// Returns an integer reduction factor that the network applies to the
// time sequence. Assumes that any 2-d is already eliminated. Used for
// scaling bounding boxes of truth data.
// WARNING: if GlobalMinimax is used to vary the scale, this will return
// the last used scale factor. Call it before any forward, and it will return
// the minimum scale factor of the paths through the GlobalMinimax.
int Series::XScaleFactor() const {
int factor = 1;
for (int i = 0; i < stack_.size(); ++i)
factor *= stack_[i]->XScaleFactor();
return factor;
}
// Provides the (minimum) x scale factor to the network (of interest only to
// input units) so they can determine how to scale bounding boxes.
void Series::CacheXScaleFactor(int factor) {
stack_[0]->CacheXScaleFactor(factor);
}
// Runs forward propagation of activations on the input line.
// See NetworkCpp for a detailed discussion of the arguments.
void Series::Forward(bool debug, const NetworkIO& input,
const TransposedArray* input_transpose,
NetworkScratch* scratch, NetworkIO* output) {
int stack_size = stack_.size();
ASSERT_HOST(stack_size > 1);
// Revolving intermediate buffers.
NetworkScratch::IO buffer1(input, scratch);
NetworkScratch::IO buffer2(input, scratch);
// Run each network in turn, giving the output of n as the input to n + 1,
// with the final network providing the real output.
stack_[0]->Forward(debug, input, input_transpose, scratch, buffer1);
for (int i = 1; i < stack_size; i += 2) {
stack_[i]->Forward(debug, *buffer1, NULL, scratch,
i + 1 < stack_size ? buffer2 : output);
if (i + 1 == stack_size) return;
stack_[i + 1]->Forward(debug, *buffer2, NULL, scratch,
i + 2 < stack_size ? buffer1 : output);
}
}
// Runs backward propagation of errors on the deltas line.
// See NetworkCpp for a detailed discussion of the arguments.
bool Series::Backward(bool debug, const NetworkIO& fwd_deltas,
NetworkScratch* scratch,
NetworkIO* back_deltas) {
if (!IsTraining()) return false;
int stack_size = stack_.size();
ASSERT_HOST(stack_size > 1);
// Revolving intermediate buffers.
NetworkScratch::IO buffer1(fwd_deltas, scratch);
NetworkScratch::IO buffer2(fwd_deltas, scratch);
// Run each network in reverse order, giving the back_deltas output of n as
// the fwd_deltas input to n-1, with the 0 network providing the real output.
if (!stack_.back()->IsTraining() ||
!stack_.back()->Backward(debug, fwd_deltas, scratch, buffer1))
return false;
for (int i = stack_size - 2; i >= 0; i -= 2) {
if (!stack_[i]->IsTraining() ||
!stack_[i]->Backward(debug, *buffer1, scratch,
i > 0 ? buffer2 : back_deltas))
return false;
if (i == 0) return needs_to_backprop_;
if (!stack_[i - 1]->IsTraining() ||
!stack_[i - 1]->Backward(debug, *buffer2, scratch,
i > 1 ? buffer1 : back_deltas))
return false;
}
return needs_to_backprop_;
}
// Splits the series after the given index, returning the two parts and
// deletes itself. The first part, up to network with index last_start, goes
// into start, and the rest goes into end.
void Series::SplitAt(int last_start, Series** start, Series** end) {
*start = NULL;
*end = NULL;
if (last_start < 0 || last_start >= stack_.size()) {
tprintf("Invalid split index %d must be in range [0,%d]!\n",
last_start, stack_.size() - 1);
return;
}
Series* master_series = new Series("MasterSeries");
Series* boosted_series = new Series("BoostedSeries");
for (int s = 0; s <= last_start; ++s) {
if (s + 1 == stack_.size() && stack_[s]->type() == NT_SOFTMAX) {
// Change the softmax to a tanh.
FullyConnected* fc = static_cast<FullyConnected*>(stack_[s]);
fc->ChangeType(NT_TANH);
}
master_series->AddToStack(stack_[s]);
stack_[s] = NULL;
}
for (int s = last_start + 1; s < stack_.size(); ++s) {
boosted_series->AddToStack(stack_[s]);
stack_[s] = NULL;
}
*start = master_series;
*end = boosted_series;
delete this;
}
// Appends the elements of the src series to this, removing from src and
// deleting it.
void Series::AppendSeries(Network* src) {
ASSERT_HOST(src->type() == NT_SERIES);
Series* src_series = static_cast<Series*>(src);
for (int s = 0; s < src_series->stack_.size(); ++s) {
AddToStack(src_series->stack_[s]);
src_series->stack_[s] = NULL;
}
delete src;
}
} // namespace tesseract.