Biases im NeuronLayer eingeführt

src/main/java/schule/ngb/zm/ml/MLMath.java

@@ -145,6 +145,37 @@ public final class MLMath {
 		return -sum / batch_size;
 	}
 
+	public static double[][] biasAdd( double[][] A, double[] V ) {
+		if( A[0].length != V.length ) {
+			throw new IllegalArgumentException("Can't add bias vector to matrix with wrong column count");
+		}
+
+		double[][] result = new double[A.length][A[0].length];
+		for( int j = 0; j < A[0].length; j++ ) {
+			for( int i = 0; i < A.length; i++ ) {
+				result[i][j] = A[i][j] + V[j];
+			}
+		}
+
+		return result;
+	}
+
+	public static double[] biasAdjust( double[] biases, double[][] delta ) {
+		if( biases.length != delta[0].length ) {
+			throw new IllegalArgumentException("Can't add adjust bias vector by delta with wrong column count");
+		}
+
+		double[] result = new double[biases.length];
+		for( int j = 0; j < delta[0].length; j++ ) {
+			for( int i = 0; i < delta.length; i++ ) {
+				result[j] += biases[j] - delta[i][j];
+			}
+			result[j] /= delta.length;
+		}
+
+		return result;
+	}
+
 	private MLMath() {
 
 	}

src/main/java/schule/ngb/zm/ml/Matrix.java

@@ -1,7 +1,11 @@
 package schule.ngb.zm.ml;
 
+import schule.ngb.zm.Constants;
+
 import java.util.Arrays;
 
+// TODO: Move Math into Matrix class
+// TODO: Implement support for optional sci libs
 public class Matrix {
 
 	private int columns, rows;
@@ -37,11 +41,11 @@ public class Matrix {
 	}
 
 	public void initializeRandom() {
-		coefficients = MLMath.matrixApply(coefficients, (d) -> Math.random());
+		coefficients = MLMath.matrixApply(coefficients, (d) -> Constants.randomGaussian());
 	}
 
 	public void initializeRandom( double lower, double upper ) {
-		coefficients = MLMath.matrixApply(coefficients, (d) -> ((upper-lower) * Math.random()) + lower);
+		coefficients = MLMath.matrixApply(coefficients, (d) -> ((upper-lower) * (Constants.randomGaussian()+1) * .5) + lower);
 	}
 
 	public void initializeIdentity() {

src/main/java/schule/ngb/zm/ml/NeuronLayer.java

@@ -1,12 +1,38 @@
 package schule.ngb.zm.ml;
 
+import java.util.Arrays;
 import java.util.function.DoubleUnaryOperator;
 import java.util.function.Function;
 
 public class NeuronLayer implements Function<double[][], double[][]> {
 
+	public static NeuronLayer fromArray( double[][] weights ) {
+		NeuronLayer layer = new NeuronLayer(weights[0].length, weights.length);
+		for( int i = 0; i < weights[0].length; i++ ) {
+			for( int j = 0; j < weights.length; j++ ) {
+				layer.weights.coefficients[i][j] = weights[i][j];
+			}
+		}
+		return layer;
+	}
+
+	public static NeuronLayer fromArray( double[][] weights, double[] biases ) {
+		NeuronLayer layer = new NeuronLayer(weights[0].length, weights.length);
+		for( int i = 0; i < weights[0].length; i++ ) {
+			for( int j = 0; j < weights.length; j++ ) {
+				layer.weights.coefficients[i][j] = weights[i][j];
+			}
+		}
+		for( int j = 0; j < biases.length; j++ ) {
+			layer.biases[j] = biases[j];
+		}
+		return layer;
+	}
+	
 	Matrix weights;
 
+	double[] biases;
+
 	NeuronLayer previous, next;
 
 	DoubleUnaryOperator activationFunction, activationFunctionDerivative;
@@ -17,6 +43,9 @@ public class NeuronLayer implements Function<double[][], double[][]> {
 		weights = new Matrix(inputs, neurons);
 		weights.initializeRandom(-1, 1);
 
+		biases = new double[neurons];
+		Arrays.fill(biases, 0.0); // TODO: Random?
+
 		activationFunction = MLMath::sigmoid;
 		activationFunctionDerivative = MLMath::sigmoidDerivative;
 	}
@@ -82,13 +111,19 @@ public class NeuronLayer implements Function<double[][], double[][]> {
 
 	@Override
 	public String toString() {
-		return weights.toString();
+		return weights.toString() + "\n" + Arrays.toString(biases);
 	}
 
 	@Override
 	public double[][] apply( double[][] inputs ) {
 		lastInput = inputs;
-		lastOutput = MLMath.matrixApply(MLMath.matrixMultiply(inputs, weights.coefficients), activationFunction);
+		lastOutput = MLMath.matrixApply(
+			MLMath.biasAdd(
+				MLMath.matrixMultiply(inputs, weights.coefficients),
+				biases
+			),
+			activationFunction
+		);
 		if( next != null ) {
 			return next.apply(lastOutput);
 		} else {
@@ -115,10 +150,15 @@ public class NeuronLayer implements Function<double[][], double[][]> {
 		}
 
 		delta = MLMath.matrixScale(error, MLMath.matrixApply(this.lastOutput, this.activationFunctionDerivative));
+		// Hier schon leraningRate anwenden?
+		// See https://towardsdatascience.com/understanding-and-implementing-neural-networks-in-java-from-scratch-61421bb6352c
+		//delta = MLMath.matrixApply(delta, ( x ) -> learningRate * x);
 		if( previous != null ) {
 			previous.backprop(delta, learningRate);
 		}
 
+		biases = MLMath.biasAdjust(biases, MLMath.matrixApply(delta, ( x ) -> learningRate * x));
+
 		adjustment = MLMath.matrixMultiply(MLMath.matrixTranspose(lastInput), delta);
 		adjustment = MLMath.matrixApply(adjustment, ( x ) -> learningRate * x);
 		this.adjustWeights(adjustment);