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cascade correlation: sticking to implementation by Fahlman and not paper

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Shin
2016-05-07 23:21:40 +02:00
parent eaafc27211
commit 0221158a56
2 changed files with 73 additions and 50 deletions
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39
include/NeuralNetwork/ConstructiveAlgorithms/CascadeCorrelation.h
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@@ -3,7 +3,6 @@
#include "../Cascade/Network.h" #include "../Cascade/Network.h"
#include "../FeedForward/Network.h" #include "../FeedForward/Network.h"
#include "../Learning/QuickPropagation.h" #include "../Learning/QuickPropagation.h"
#include "../ActivationFunction/Tangents.h"
#include <random> #include <random>
#include <algorithm> #include <algorithm>
@@ -22,16 +21,16 @@ namespace NeuralNetwork {
std::size_t inputs = patterns[0].first.size(); std::size_t inputs = patterns[0].first.size();
std::size_t outputs = patterns[0].second.size(); std::size_t outputs = patterns[0].second.size();
Cascade::Network network(inputs, outputs, NeuralNetwork::ActivationFunction::Tangents()); Cascade::Network network(inputs, outputs, *_activFunction.get());
network.randomizeWeights(); network.randomizeWeights();
int step = 0; std::size_t step = 0;
float error = trainOutputs(network, patterns); float error = trainOutputs(network, patterns);
while(step++ < 15 && error > _maxError) { while(step++ < _maxHiddenUnits && error > _maxError) {
std::vector<std::shared_ptr<Neuron>> candidates = createCandidates(network.getNeuronSize() - outputs); std::vector<std::shared_ptr<Neuron>> candidates = createCandidates(network.getNeuronSize() - outputs);
std::shared_ptr<Neuron> candidate=trainCandidates(network, candidates, patterns); std::pair<std::shared_ptr<Neuron>, std::vector<float>> candidate = trainCandidates(network, candidates, patterns);
addBestCandidate(network, candidate); addBestCandidate(network, candidate);
error = trainOutputs(network, patterns); error = trainOutputs(network, patterns);
@@ -59,10 +58,20 @@ namespace NeuralNetwork {
_distribution = std::uniform_real_distribution<>(-weightRange, weightRange); _distribution = std::uniform_real_distribution<>(-weightRange, weightRange);
} }
void setMaximumHiddenNeurons(std::size_t neurons) {
_maxHiddenUnits = neurons;
}
void setActivationFunction(const ActivationFunction::ActivationFunction &function) {
_activFunction = std::shared_ptr<ActivationFunction::ActivationFunction>(function.clone());
}
protected: protected:
std::shared_ptr<ActivationFunction::ActivationFunction> _activFunction = std::make_shared<ActivationFunction::Sigmoid>(-4.9);
float _minimalErrorStep = 0.00005; float _minimalErrorStep = 0.00005;
float _maxError; float _maxError;
float _weightRange; float _weightRange;
std::size_t _maxHiddenUnits = 20;
std::size_t _numberOfCandidates; std::size_t _numberOfCandidates;
std::mt19937 _generator; std::mt19937 _generator;
std::uniform_real_distribution<> _distribution; std::uniform_real_distribution<> _distribution;
@@ -84,19 +93,23 @@ namespace NeuralNetwork {
float trainOutputs(Cascade::Network &network, const std::vector<TrainingPattern> &patterns); float trainOutputs(Cascade::Network &network, const std::vector<TrainingPattern> &patterns);
std::shared_ptr<Neuron> trainCandidates(Cascade::Network &network, std::vector<std::shared_ptr<Neuron>> &candidates, const std::vector<TrainingPattern> &patterns); std::pair<std::shared_ptr<Neuron>, std::vector<float>> trainCandidates(Cascade::Network &network, std::vector<std::shared_ptr<Neuron>> &candidates,
const std::vector<TrainingPattern> &patterns);
void addBestCandidate(Cascade::Network &network, const std::shared_ptr<Neuron> &candidate) { void addBestCandidate(Cascade::Network &network, const std::pair<std::shared_ptr<Neuron>, std::vector<float>> &candidate) {
auto neuron = network.addNeuron(); auto neuron = network.addNeuron();
neuron->setWeights(candidate->getWeights()); float weightPortion = network.getNeuronSize() - network.outputs();
neuron->setActivationFunction(candidate->getActivationFunction()); neuron->setWeights(candidate.first->getWeights());
neuron->setActivationFunction(candidate.first->getActivationFunction());
std::size_t outIndex = 0;
for(auto &n :network.getOutputNeurons()) { for(auto &n :network.getOutputNeurons()) {
auto weights = n->getWeights(); auto weights = n->getWeights();
for(auto& weight: weights) { for(auto &weight: weights) {
weight *=0.7; weight *= 0.7;
} }
weights[weights.size()-1] = _distribution(_generator); weights[weights.size() - 1] = -candidate.second[outIndex] * weightPortion;//_distribution(_generator);
outIndex++;
n->setWeights(weights); n->setWeights(weights);
} }
} }
@@ -107,7 +120,7 @@ namespace NeuralNetwork {
for(std::size_t i = 0; i < _numberOfCandidates; i++) { for(std::size_t i = 0; i < _numberOfCandidates; i++) {
candidates.push_back(std::make_shared<Neuron>(id)); candidates.push_back(std::make_shared<Neuron>(id));
candidates.back()->setInputSize(id); candidates.back()->setInputSize(id);
candidates.back()->setActivationFunction(NeuralNetwork::ActivationFunction::Tangents()); candidates.back()->setActivationFunction(*_activFunction.get());
for(std::size_t weightIndex = 0; weightIndex < id; weightIndex++) { for(std::size_t weightIndex = 0; weightIndex < id; weightIndex++) {
candidates.back()->weight(weightIndex) = _distribution(_generator); candidates.back()->weight(weightIndex) = _distribution(_generator);

84
src/NeuralNetwork/ConstructiveAlgorithms/CascadeCorrelation.cpp
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@@ -5,55 +5,58 @@ using namespace NeuralNetwork::ConstructiveAlgorihtms;
float CascadeCorrelation::trainOutputs(Cascade::Network &network, const std::vector<CascadeCorrelation::TrainingPattern> &patterns) { float CascadeCorrelation::trainOutputs(Cascade::Network &network, const std::vector<CascadeCorrelation::TrainingPattern> &patterns) {
std::size_t outputs = patterns[0].second.size(); std::size_t outputs = patterns[0].second.size();
FeedForward::Network p(network.getNeuronSize() - outputs-1); FeedForward::Network p(network.getNeuronSize() - outputs - 1);
p.appendLayer(outputs); p.appendLayer(outputs);
Learning::QuickPropagation learner(p); Learning::QuickPropagation learner(p);
for(std::size_t neuron = 0; neuron < outputs; neuron++) { for(std::size_t neuron = 0; neuron < outputs; neuron++) {
p[1][neuron+1].setWeights(network.getNeuron(network.getNeuronSize() - outputs + neuron)->getWeights()); p[1][neuron + 1].setWeights(network.getNeuron(network.getNeuronSize() - outputs + neuron)->getWeights());
p[1][neuron+1].setActivationFunction(network.getNeuron(network.getNeuronSize() - outputs + neuron)->getActivationFunction()); p[1][neuron + 1].setActivationFunction(network.getNeuron(network.getNeuronSize() - outputs + neuron)->getActivationFunction());
} }
//std::cout << p.stringify() << "\n"; //std::cout << p.stringify() << "\n";
std::vector<TrainingPattern> patternsForOutput; std::vector<TrainingPattern> patternsForOutput;
for(auto &pattern:patterns) { for(auto &pattern:patterns) {
patternsForOutput.emplace_back(getInnerNeuronsOutput(network,pattern.first), pattern.second); patternsForOutput.emplace_back(getInnerNeuronsOutput(network, pattern.first), pattern.second);
} }
float lastError = std::numeric_limits<float>::max(); float lastError;
float error = std::numeric_limits<float>::max(); float error = std::numeric_limits<float>::max();
std::size_t iteration = 0; std::size_t iteration = 0;
std::size_t iterWithoutImporvement=0; std::size_t iterWithoutImporvement = 0;
do { do {
lastError=error; lastError = error;
for(auto &pattern:patternsForOutput) { for(auto &pattern:patternsForOutput) {
learner.teach({pattern.first.begin()+1,pattern.first.end()}, pattern.second); learner.teach({pattern.first.begin() + 1, pattern.first.end()}, pattern.second);
} }
error = 0; error = 0;
for(auto &pattern:patternsForOutput) { for(auto &pattern:patternsForOutput) {
std::vector<float> output = p.computeOutput(pattern.first); std::vector<float> output = p.computeOutput({pattern.first.begin() + 1, pattern.first.end()});
for(std::size_t outputIndex = 0; outputIndex < output.size(); outputIndex++) { for(std::size_t outputIndex = 0; outputIndex < output.size(); outputIndex++) {
error += pow(output[outputIndex] - pattern.second[outputIndex],2); error += pow(output[outputIndex] - pattern.second[outputIndex], 2);
} }
} }
if(fabs(lastError - error) < _minimalErrorStep) { if(fabs(lastError - error) < _minimalErrorStep) {
iterWithoutImporvement++; iterWithoutImporvement++;
}else { } else {
iterWithoutImporvement=0; iterWithoutImporvement = 0;
} }
} while (iteration++ < 1000 && iterWithoutImporvement < 3); }
std::cout << "iter: " << iteration << ", error: " << error << ", " << (lastError-error) << "\n"; while(iteration++ < 1000 && iterWithoutImporvement < 400);
std::cout << "iter: " << iteration << ", error: " << error << ", " << (lastError - error) << "\n";
for(std::size_t neuron = 0; neuron < outputs; neuron++) { for(std::size_t neuron = 0; neuron < outputs; neuron++) {
network.getNeuron(network.getNeuronSize() - outputs + neuron)->setWeights(p[1][neuron+1].getWeights()); network.getNeuron(network.getNeuronSize() - outputs + neuron)->setWeights(p[1][neuron + 1].getWeights());
} }
return error; return error;
} }
std::shared_ptr<NeuralNetwork::Neuron> CascadeCorrelation::trainCandidates(Cascade::Network &network, std::vector<std::shared_ptr<Neuron>> &candidates, const std::vector<TrainingPattern> &patterns) { std::pair<std::shared_ptr<NeuralNetwork::Neuron>, std::vector<float>> CascadeCorrelation::trainCandidates(Cascade::Network &network,
std::vector<std::shared_ptr<Neuron>> &candidates,
const std::vector<TrainingPattern> &patterns) {
std::size_t outputs = patterns[0].second.size(); std::size_t outputs = patterns[0].second.size();
std::vector<TrainingPattern> patternsForOutput; std::vector<TrainingPattern> patternsForOutput;
@@ -62,31 +65,34 @@ std::shared_ptr<NeuralNetwork::Neuron> CascadeCorrelation::trainCandidates(Casca
patternsForOutput.emplace_back(getInnerNeuronsOutput(network, pattern.first), pattern.second); patternsForOutput.emplace_back(getInnerNeuronsOutput(network, pattern.first), pattern.second);
} }
std::vector<std::vector<float>> errors (patterns.size()); std::vector<std::vector<float>> errors(patterns.size());
std::vector<float> meanErrors (outputs); std::vector<float> meanErrors(outputs);
for(std::size_t patternNumber = 0; patternNumber < patterns.size(); patternNumber++) { for(std::size_t patternNumber = 0; patternNumber < patterns.size(); patternNumber++) {
auto &pattern=patterns[patternNumber]; auto &pattern = patterns[patternNumber];
errors[patternNumber].resize(network.outputs()); errors[patternNumber].resize(network.outputs());
std::vector<float> output = network.computeOutput(patterns[patternNumber].first); std::vector<float> output = network.computeOutput(patterns[patternNumber].first);
for(std::size_t outputIndex = 0; outputIndex < network.outputs(); outputIndex++) { for(std::size_t outputIndex = 0; outputIndex < network.outputs(); outputIndex++) {
float error = pow(pattern.second[outputIndex] - output[outputIndex],2); float error = pow(pattern.second[outputIndex] - output[outputIndex], 2);
errors[patternNumber][outputIndex]=error; errors[patternNumber][outputIndex] = error;
meanErrors[outputIndex] += error; meanErrors[outputIndex] += error;
} }
} }
std::for_each(meanErrors.begin(), meanErrors.end(), [&patterns](float &n){ n/=patterns.size(); }); std::for_each(meanErrors.begin(), meanErrors.end(), [&patterns](float &n) { n /= patterns.size(); });
std::size_t iterations=0;
std::size_t iterationsWithoutIprovement=0; std::size_t iterations = 0;
float bestCorrelation=0; std::size_t iterationsWithoutIprovement = 0;
float lastCorrelation=0; float bestCorrelation = 0;
std::shared_ptr<Neuron> bestCandidate=nullptr; float lastCorrelation = 0;
std::shared_ptr<Neuron> bestCandidate = nullptr;
std::vector<float> bestCorrelations(errors[0].size());
do { do {
lastCorrelation = bestCorrelation; lastCorrelation = bestCorrelation;
bool firstStep=true; bool firstStep = true;
for(auto&candidate : candidates) { for(auto &candidate : candidates) {
float correlation; float correlation;
std::vector<float> activations; std::vector<float> activations;
@@ -104,7 +110,8 @@ std::shared_ptr<NeuralNetwork::Neuron> CascadeCorrelation::trainCandidates(Casca
correlationSigns[err] = correlations[err] > 0 ? 1.0 : -1.0; correlationSigns[err] = correlations[err] > 0 ? 1.0 : -1.0;
} }
correlation = std::accumulate(correlations.begin(), correlations.end(), 0.0); correlation = std::accumulate(correlations.begin(), correlations.end(), 0.0, [](const float &a, float b) { return a + fabs(b); });
std::vector<float> derivatives(candidate->getWeights().size()); std::vector<float> derivatives(candidate->getWeights().size());
for(std::size_t input = 0; input < candidate->getWeights().size(); input++) { for(std::size_t input = 0; input < candidate->getWeights().size(); input++) {
float dcdw = 0.0; float dcdw = 0.0;
@@ -122,13 +129,14 @@ std::shared_ptr<NeuralNetwork::Neuron> CascadeCorrelation::trainCandidates(Casca
} }
for(std::size_t weightIndex = 0; weightIndex < derivatives.size(); weightIndex++) { for(std::size_t weightIndex = 0; weightIndex < derivatives.size(); weightIndex++) {
candidate->weight(weightIndex) += derivatives[weightIndex] * 0.1; candidate->weight(weightIndex) += derivatives[weightIndex] * 0.7;
} }
if(firstStep || correlation > bestCorrelation) { if(firstStep || correlation > bestCorrelation) {
bestCorrelation = correlation; bestCorrelation = correlation;
bestCandidate=candidate; bestCandidate = candidate;
firstStep=false; std::swap(bestCorrelations, correlations);
firstStep = false;
} }
} }
@@ -136,8 +144,10 @@ std::shared_ptr<NeuralNetwork::Neuron> CascadeCorrelation::trainCandidates(Casca
iterationsWithoutIprovement++; iterationsWithoutIprovement++;
} }
} while (iterations ++ < 200 && iterationsWithoutIprovement <3); }
std::cout << "iter: " << iterations << ", correlation: " << bestCorrelation << ", " << lastCorrelation << "\n"; while(iterations++ < 200 && iterationsWithoutIprovement < 300);
std::cout << "iter: " << iterations << ", correlation: " << bestCorrelation << ", " << lastCorrelation << "\n";
return {bestCandidate, bestCorrelations};
}
return bestCandidate;
}