void ComputeDeltas(int layer, INeuralNetAccessor outputGradient)
{
float sigmoidDash;
float error;
int numberOfNodes = neuralNetAccessor.NodesInLayer(layer);
int numberOfNextLayerNodes = neuralNetAccessor.NodesInLayer(layer + 1);
NeuralLayer neuralLayer = neuralNetAccessor.GetNeuralLayer(layer);
for (int node = 0; node < numberOfNodes; node++)
{
// Compute sigmoidDash
//sigmoidDash = neuralLayer.GetNode(node).Compute(weightedInputs[layer][node] + smallDelta) - activations[layer][node];
sigmoidDash = activations[layer][node];
sigmoidDash = sigmoidDash * (1 - sigmoidDash);
// Compute error
error = 0;
for (int nextNode = 0; nextNode < numberOfNextLayerNodes; nextNode++)
{
error += outputGradient.BiasAccessor[layer + 1, nextNode] * outputGradient.WeightAccessor[layer, nextNode, node];
}
// Comput delta
outputGradient.BiasAccessor[layer, node] = sigmoidDash * error;
}
}
void ComputeLastDeltas(float[] learningExampleOutput, INeuralNetAccessor outputGradient)
{
float sigmoidDash;
float deltaCa;
int lastLayer = neuralNetAccessor.NumberOfLayers - 1;
int numberOfFinalNodes = neuralNetAccessor.NodesInLayer(lastLayer);
NeuralLayer lastNeuralLayer = neuralNetAccessor.GetNeuralLayer(lastLayer);
for (int i = 0; i < numberOfFinalNodes; i++)
{
//sigmoidDash = lastNeuralLayer.GetNode(i).Compute(weightedInputs[lastLayer][i] + smallDelta) - activations[lastLayer][i];
sigmoidDash = activations[lastLayer][i];
sigmoidDash = sigmoidDash * (1 - sigmoidDash);
deltaCa = activations[lastLayer][i] - learningExampleOutput[i];
outputGradient.BiasAccessor[lastLayer, i] = sigmoidDash * deltaCa;
}
}
public NeuralNetAccessor(params int[] layersNodes)
{
if (layersNodes.Length < 2)
{
throw new System.ArgumentException();
}
int inputSize = layersNodes[0];
neuralLayers = new NeuralLayer[layersNodes.Length - 1];
int currentNumberOfWeights = inputSize;
for (int i = 0; i < neuralLayers.Length; i++)
{
neuralLayers[i] = new NeuralLayer(currentNumberOfWeights, layersNodes[i + 1]);
currentNumberOfWeights = layersNodes[i + 1];
}
initializedParameters = new int[layersNodes.Length];
for (int i = 0; i < layersNodes.Length; i++)
{
initializedParameters[i] = layersNodes[i];
}
}
