Streams durch Schleifen ersetzt

Der Overhead durch die parallelen Streams war zu hoch. Jedenfalls bei den relativ kleinen Matrizen im Test. Bei größeren Matrizen könnte die Parallelität einen Vorteil bringen. Ggf. sollte dies getesett werden und abhängig von der Größe die bestte Methode gewählt werden.

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

@@ -2,9 +2,7 @@ package schule.ngb.zm.ml;
 
 import schule.ngb.zm.Constants;
 
-import java.util.Arrays;
 import java.util.function.DoubleUnaryOperator;
-import java.util.stream.IntStream;
 
 // TODO: Move Math into Matrix class
 // TODO: Implement support for optional sci libs
@@ -12,20 +10,33 @@ public final class DoubleMatrix implements MLMatrix {
 
 	private int columns, rows;
 
-	double[][] coefficients;
+	double[] coefficients;
 
 	public DoubleMatrix( int rows, int cols ) {
 		this.rows = rows;
 		this.columns = cols;
-		coefficients = new double[rows][cols];
+		coefficients = new double[rows * cols];
 	}
 
 	public DoubleMatrix( double[][] coefficients ) {
 		this.rows = coefficients.length;
 		this.columns = coefficients[0].length;
-		this.coefficients = Arrays.stream(coefficients)
-				.map(double[]::clone)
-				.toArray(double[][]::new);
+		this.coefficients = new double[rows * columns];
+		for( int j = 0; j < columns; j++ ) {
+			for( int i = 0; i < rows; i++ ) {
+				this.coefficients[idx(i, j)] = coefficients[i][j];
+			}
+		}
+	}
+
+	public DoubleMatrix( DoubleMatrix other ) {
+		this.rows = other.rows();
+		this.columns = other.columns();
+		this.coefficients = new double[rows * columns];
+		System.arraycopy(
+			other.coefficients, 0,
+			this.coefficients, 0,
+			rows * columns);
 	}
 
 	public int columns() {
@@ -37,15 +48,19 @@ public final class DoubleMatrix implements MLMatrix {
 	}
 
 	public double[][] coefficients() {
-		return coefficients;
+		return new double[rows][columns];
+	}
+
+	int idx( int r, int c ) {
+		return c * rows + r;
 	}
 
 	public double get( int row, int col ) {
-		return coefficients[row][col];
+		return coefficients[idx(row, col)];
 	}
 
 	public MLMatrix set( int row, int col, double value ) {
-		coefficients[row][col] = value;
+		coefficients[idx(row, col)] = value;
 		return this;
 	}
 
@@ -54,145 +69,202 @@ public final class DoubleMatrix implements MLMatrix {
 	}
 
 	public MLMatrix initializeRandom( double lower, double upper ) {
-		applyInPlace((d) -> ((upper-lower) * Constants.random()) + lower);
+		applyInPlace(( d ) -> ((upper - lower) * Constants.random()) + lower);
 		return this;
 	}
 
 	public MLMatrix initializeOne() {
-		applyInPlace((d) -> 1.0);
+		applyInPlace(( d ) -> 1.0);
 		return this;
 	}
 
 	public MLMatrix initializeZero() {
-		applyInPlace((d) -> 0.0);
+		applyInPlace(( d ) -> 0.0);
 		return this;
 	}
 
 	@Override
 	public MLMatrix duplicate() {
-		return new DoubleMatrix(coefficients);
+		return new DoubleMatrix(this);
 	}
 
 	@Override
 	public MLMatrix multiplyTransposed( MLMatrix B ) {
-		return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
+		/*return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
 			( i ) -> IntStream.range(0, B.rows()).mapToDouble(
 				( j ) -> IntStream.range(0, columns).mapToDouble(
-					(k) -> coefficients[i][k]*B.get(j,k)
+					( k ) -> get(i, k) * B.get(j, k)
 				).sum()
 			).toArray()
-		).toArray(double[][]::new));
+		).toArray(double[][]::new));*/
+		DoubleMatrix result = new DoubleMatrix(rows, B.rows());
+		for( int i = 0; i < rows; i++ ) {
+			for( int j = 0; j < B.rows(); j++ ) {
+				result.coefficients[result.idx(i, j)] = 0.0;
+				for( int k = 0; k < columns; k++ ) {
+					result.coefficients[result.idx(i, j)] += get(i, k) * B.get(j, k);
+				}
+			}
+		}
+		return result;
 	}
 
 	@Override
 	public MLMatrix multiplyAddBias( final MLMatrix B, final MLMatrix C ) {
-		return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
+		/*return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
 			( i ) -> IntStream.range(0, B.columns()).mapToDouble(
 				( j ) -> IntStream.range(0, columns).mapToDouble(
-					(k) -> coefficients[i][k]*B.get(k,j)
+					( k ) -> get(i, k) * B.get(k, j)
 				).sum() + C.get(0, j)
 			).toArray()
-		).toArray(double[][]::new));
+		).toArray(double[][]::new));*/
+		DoubleMatrix result = new DoubleMatrix(rows, B.columns());
+		for( int i = 0; i < rows; i++ ) {
+			for( int j = 0; j < B.columns(); j++ ) {
+				result.coefficients[result.idx(i, j)] = 0.0;
+				for( int k = 0; k < columns; k++ ) {
+					result.coefficients[result.idx(i, j)] += get(i, k) * B.get(k, j);
+				}
+				result.coefficients[result.idx(i, j)] += C.get(0, j);
+			}
+		}
+		return result;
 	}
 
 	@Override
 	public MLMatrix transposedMultiplyAndScale( final MLMatrix B, final double scalar ) {
-		return new DoubleMatrix(IntStream.range(0, columns).parallel().mapToObj(
+		/*return new DoubleMatrix(IntStream.range(0, columns).parallel().mapToObj(
 			( i ) -> IntStream.range(0, B.columns()).mapToDouble(
 				( j ) -> IntStream.range(0, rows).mapToDouble(
-					(k) -> coefficients[k][i]*B.get(k,j)*scalar
+					( k ) -> get(k, i) * B.get(k, j) * scalar
 				).sum()
 			).toArray()
-		).toArray(double[][]::new));
+		).toArray(double[][]::new));*/
+		DoubleMatrix result = new DoubleMatrix(columns, B.columns());
+		for( int i = 0; i < columns; i++ ) {
+			for( int j = 0; j < B.columns(); j++ ) {
+				result.coefficients[result.idx(i, j)] = 0.0;
+				for( int k = 0; k < rows; k++ ) {
+					result.coefficients[result.idx(i, j)] += get(k, i) * B.get(k, j);
+				}
+				result.coefficients[result.idx(i, j)] *= scalar;
+			}
+		}
+		return result;
 	}
 
 	@Override
 	public MLMatrix add( MLMatrix B ) {
-		return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
+		/*return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
 			( i ) -> IntStream.range(0, columns).mapToDouble(
-				( j ) -> coefficients[i][j] + B.get(i, j)
+				( j ) -> get(i, j) + B.get(i, j)
 			).toArray()
-		).toArray(double[][]::new));
+		).toArray(double[][]::new));*/
+		DoubleMatrix sum = new DoubleMatrix(rows, columns);
+		for( int j = 0; j < columns; j++ ) {
+			for( int i = 0; i < rows; i++ ) {
+				sum.coefficients[idx(i, j)] = coefficients[idx(i, j)] + B.get(i, j);
+			}
+		}
+		return sum;
 	}
 
 	@Override
 	public MLMatrix addInPlace( MLMatrix B ) {
-		coefficients = IntStream.range(0, rows).parallel().mapToObj(
-			( i ) -> IntStream.range(0, columns).mapToDouble(
-				( j ) -> coefficients[i][j] + B.get(i, j)
-			).toArray()
-		).toArray(double[][]::new);
+		for( int j = 0; j < columns; j++ ) {
+			for( int i = 0; i < rows; i++ ) {
+				coefficients[idx(i, j)] += B.get(i, j);
+			}
+		}
 		return this;
 	}
 
 	@Override
 	public MLMatrix sub( MLMatrix B ) {
-		return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
+		/*return new DoubleMatrix(IntStream.range(0, rows).parallel().mapToObj(
 			( i ) -> IntStream.range(0, columns).mapToDouble(
-				( j ) -> coefficients[i][j] - B.get(i, j)
+				( j ) -> get(i, j) - B.get(i, j)
 			).toArray()
-		).toArray(double[][]::new));
+		).toArray(double[][]::new));*/
+		DoubleMatrix diff = new DoubleMatrix(rows, columns);
+		for( int j = 0; j < columns; j++ ) {
+			for( int i = 0; i < rows; i++ ) {
+				diff.coefficients[idx(i, j)] = coefficients[idx(i, j)] - B.get(i, j);
+			}
+		}
+		return diff;
 	}
 
 	@Override
 	public MLMatrix colSums() {
-		double[][] sums = new double[1][columns];
-		for( int c = 0; c < columns; c++ ) {
-			for( int r = 0; r < rows; r++ ) {
-				sums[0][c] += coefficients[r][c];
+		/*DoubleMatrix colSums = new DoubleMatrix(1, columns);
+		colSums.coefficients = IntStream.range(0, columns).parallel().mapToDouble(
+			( j ) -> IntStream.range(0, rows).mapToDouble(
+				( i ) -> get(i, j)
+			).sum()
+		).toArray();
+		return colSums;*/
+		DoubleMatrix colSums = new DoubleMatrix(1, columns);
+		for( int j = 0; j < columns; j++ ) {
+			colSums.coefficients[j] = 0.0;
+			for( int i = 0; i < rows; i++ ) {
+				colSums.coefficients[j] += coefficients[idx(i, j)];
 			}
 		}
-		return new DoubleMatrix(sums);
+		return colSums;
 	}
 
 	@Override
 	public MLMatrix scaleInPlace( final double scalar ) {
-		coefficients = Arrays.stream(coefficients).parallel().map(
-			( arr ) -> Arrays.stream(arr).map(
-				(d) -> d * scalar
-			).toArray()
-		).toArray(double[][]::new);
+		for( int i = 0; i < coefficients.length; i++ ) {
+			coefficients[i] *= scalar;
+		}
 		return this;
 	}
 
 	@Override
 	public MLMatrix scaleInPlace( final MLMatrix S ) {
-		coefficients = IntStream.range(0, coefficients.length).parallel().mapToObj(
-			( i ) -> IntStream.range(0, coefficients[i].length).mapToDouble(
-				( j ) -> coefficients[i][j] * S.get(i, j)
-			).toArray()
-		).toArray(double[][]::new);
+		for( int j = 0; j < columns; j++ ) {
+			for( int i = 0; i < rows; i++ ) {
+				coefficients[idx(i, j)] *= S.get(i, j);
+			}
+		}
 		return this;
 	}
 
 	@Override
 	public MLMatrix apply( DoubleUnaryOperator op ) {
-		return new DoubleMatrix(Arrays.stream(coefficients).parallel().map(
-			( arr ) -> Arrays.stream(arr).map(op).toArray()
-		).toArray(double[][]::new));
+		DoubleMatrix result = new DoubleMatrix(rows, columns);
+		for( int i = 0; i < coefficients.length; i++ ) {
+			result.coefficients[i] = op.applyAsDouble(coefficients[i]);
+		}
+		return result;
 	}
 
 	@Override
 	public MLMatrix applyInPlace( DoubleUnaryOperator op ) {
-		this.coefficients = Arrays.stream(coefficients).parallel().map(
-			( arr ) -> Arrays.stream(arr).map(op).toArray()
-		).toArray(double[][]::new);
+		for( int i = 0; i < coefficients.length; i++ ) {
+			coefficients[i] = op.applyAsDouble(coefficients[i]);
+		}
 		return this;
 	}
 
 	@Override
 	public String toString() {
-		//return Arrays.deepToString(coefficients);
 		StringBuilder sb = new StringBuilder();
-		sb.append('[');
+		sb.append(rows);
+		sb.append(" x ");
+		sb.append(columns);
+		sb.append(" Matrix");
 		sb.append('\n');
-		for( int i = 0; i < coefficients.length; i++ ) {
-			sb.append('\t');
-			sb.append(Arrays.toString(coefficients[i]));
+		for( int i = 0; i < rows; i++ ) {
+			for( int j = 0; j < columns; j++ ) {
+				sb.append(get(i, j));
+				if( j < columns - 1 )
+					sb.append(' ');
+			}
 			sb.append('\n');
 		}
-		sb.append(']');
-
 		return sb.toString();
 	}