private void TrainWithBackpropagation(TrainingSuite trainingSuite, int trainingDataBegin, int trainingDataEnd, ComputeDevice calculator)
{
//Calculate the accumulated gradient. Accumulated means, that the gradient has to be divided by the number of samples in the minibatch.
List <List <NeuronData> > accumulatedGradient = null;
accumulatedGradient = calculator.CalculateAccumulatedGradientForMinibatch(this, trainingSuite, trainingDataBegin, trainingDataEnd);
float sizeDivisor = (float)(trainingDataEnd - trainingDataBegin) / (float)trainingSuite.trainingData.Count;
//Calculate regularization terms based on the training configuration
float regularizationTerm1 = 1.0f;
float regularizationTerm2Base = 0.0f;
if (trainingSuite.config.regularization == TrainingConfig.Regularization.L2)
{
regularizationTerm1 = 1.0f - trainingSuite.config.learningRate * (trainingSuite.config.regularizationLambda / (float)trainingSuite.trainingData.Count);
}
else if (trainingSuite.config.regularization == TrainingConfig.Regularization.L1)
{
regularizationTerm2Base = -((trainingSuite.config.learningRate * (trainingSuite.config.regularizationLambda / (float)trainingSuite.trainingData.Count)));
}
bool applyRegularizationTerm2 = trainingSuite.config.regularization == TrainingConfig.Regularization.L1;
//Apply accumulated gradient to network (Gradient descent)
float sizeDivisorAndLearningRate = sizeDivisor * trainingSuite.config.learningRate;
for (int i = 0; i < layers.Count; ++i)
{
var layer = layers[i];
var weightsPerNeuron = layer.GetWeightsPerNeuron();
var layerNeuronCount = layer.GetNeuronCount();
var weightMx = layer.weightMx;
var biases = layer.biases;
for (int j = 0; j < layerNeuronCount; ++j)
{
var layerGradientWeights = accumulatedGradient[i][j].weights;
biases[j] -= accumulatedGradient[i][j].bias * sizeDivisorAndLearningRate;
for (int w = 0; w < weightsPerNeuron; ++w)
{
weightMx[j, w] = regularizationTerm1 * weightMx[j, w] - layerGradientWeights[w] * sizeDivisorAndLearningRate;
if (applyRegularizationTerm2)
{
weightMx[j, w] -= regularizationTerm2Base * Utils.Sign(weightMx[j, w]);
}
}
}
}
}
/// <summary>
/// Trains the network using the given training suite and calculator
/// The functions returns immediately with a promise object that can be used to monitor progress.
/// Note: Using the network during training is not permitted.
/// </summary>
/// <param name="trainingSuite">The training suite to be used</param>
/// <param name="calculator">The calculator (containing a compute device) to be used for calculations</param>
/// <returns>A promise that can be used to check the </returns>
public TrainingPromise Train(TrainingSuite trainingSuite, ComputeDevice calculator)
{
if (trainingPromise != null)
{
throw new Exception("Cannot perform operation while training is in progress!");
}
trainingPromise = new TrainingPromise();
if (trainingSuite.config.epochs < 1)
{
trainingPromise.SetProgress(1, 0);
return(trainingPromise);
}
trainingThread = new Thread(() => {
for (int currentEpoch = 0; currentEpoch < trainingSuite.config.epochs; currentEpoch++)
{
if (trainingPromise.IsStopAtNextEpoch())
{
break;
}
if (trainingSuite.config.shuffleTrainingData)
{
Utils.ShuffleList(ref trainingSuite.trainingData);
}
int trainingDataBegin = 0;
int trainingDataEnd = trainingSuite.config.UseMinibatches() ? Math.Min(trainingSuite.config.miniBatchSize, trainingSuite.trainingData.Count) : trainingSuite.trainingData.Count;
while (true)
{
//Calculate the accumulated gradient. Accumulated means, that the gradient has to be divided by the number of samples in the minibatch.
List <List <NeuronData> > accumulatedGradient = null;
accumulatedGradient = calculator.CalculateAccumulatedGradientForMinibatch(this, trainingSuite, trainingDataBegin, trainingDataEnd);
float sizeDivisor = (float)(trainingDataEnd - trainingDataBegin) / (float)trainingSuite.trainingData.Count;
//Calculate regularization terms based on the training configuration
float regularizationTerm1 = 1.0f;
float regularizationTerm2Base = 0.0f;
if (trainingSuite.config.regularization == TrainingSuite.TrainingConfig.Regularization.L2)
{
regularizationTerm1 = 1.0f - trainingSuite.config.learningRate * (trainingSuite.config.regularizationLambda / (float)trainingSuite.trainingData.Count);
}
else if (trainingSuite.config.regularization == TrainingSuite.TrainingConfig.Regularization.L1)
{
regularizationTerm2Base = -((trainingSuite.config.learningRate * (trainingSuite.config.regularizationLambda / (float)trainingSuite.trainingData.Count)));
}
bool applyRegularizationTerm2 = trainingSuite.config.regularization == TrainingSuite.TrainingConfig.Regularization.L1;
//Apply accumulated gradient to network (Gradient descent)
float sizeDivisorAndLearningRate = sizeDivisor * trainingSuite.config.learningRate;
for (int i = 0; i < layers.Count; ++i)
{
var layer = layers[i];
var weightsPerNeuron = layer.GetWeightsPerNeuron();
var layerNeuronCount = layer.GetNeuronCount();
var weightMx = layer.weightMx;
var biases = layer.biases;
for (int j = 0; j < layerNeuronCount; ++j)
{
var layerGradientWeights = accumulatedGradient[i][j].weights;
biases[j] -= accumulatedGradient[i][j].bias * sizeDivisorAndLearningRate;
for (int w = 0; w < weightsPerNeuron; ++w)
{
weightMx[j, w] = regularizationTerm1 * weightMx[j, w] - layerGradientWeights[w] * sizeDivisorAndLearningRate;
if (applyRegularizationTerm2)
{
weightMx[j, w] -= regularizationTerm2Base * Utils.Sign(weightMx[j, w]);
}
}
}
}
//Set up the next minibatch, or quit the loop if we're done.
if (trainingSuite.config.UseMinibatches())
{
if (trainingDataEnd >= trainingSuite.trainingData.Count)
{
break;
}
trainingPromise.SetProgress(((float)trainingDataEnd + ((float)currentEpoch * (float)trainingSuite.trainingData.Count)) / ((float)trainingSuite.trainingData.Count * (float)trainingSuite.config.epochs), currentEpoch + 1);
trainingDataBegin = trainingDataEnd;
trainingDataEnd = Math.Min(trainingDataEnd + trainingSuite.config.miniBatchSize, trainingSuite.trainingData.Count);
}
else
{
break;
}
}
}
calculator.FlushWorkingCache(); //Release any cache that the mathLib has built up.
trainingPromise.SetProgress(1, trainingPromise.GetEpochsDone()); //Report that the training is finished
trainingPromise = null;
});
trainingThread.Start();
return(trainingPromise);
}