view src/samer/maths/MatrixTimesVector.java @ 0:bf79fb79ee13

Initial Mercurial check in.

/*
 *	Copyright (c) 2000, Samer Abdallah, King's College London.
 *	All rights reserved.
 *
 *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
 *	without even the implied warranty of MERCHANTABILITY or 
 *	FITNESS FOR A PARTICULAR PURPOSE.
 */

package samer.maths;
import  samer.tools.*;

public class MatrixTimesVector extends VectorFunctionOfVector implements SafeTask
{
	int m, n;
	double [][] a;
	double [] x, y, arow;

	public MatrixTimesVector( Vec out, Matrix matrix, Vec in) {
		this(out.array(),matrix,in.array());
	}

	public MatrixTimesVector(Matrix matrix)
	{
		n = matrix.getRowDimension();
		m = matrix.getColumnDimension();
		a = matrix.getArray();
	}
	
	public MatrixTimesVector( double [] out, Matrix matrix)
	{
		n = matrix.getRowDimension();
		m = matrix.getColumnDimension();
		a = matrix.getArray();
		y = out;
	}

	public MatrixTimesVector( double [] out, Matrix matrix, double [] in)
	{
		n = matrix.getRowDimension();
		m = matrix.getColumnDimension();
		a = matrix.getArray();
		x = in;
		y = out;
	}

	public void dispose() {}
	public void starting() {}
	public void stopping() {}
	public void run() {
		for (int i=0; i<n; i++) {
			double t=0;
			arow=a[i];
			for (int j=0; j<m; j++) t+=arow[j]*x[j];
			y[i]=t;
		}
	}

	public void apply(double [] x, double [] y) {
		for (int i=0; i<n; i++) {
			double t=0;
			arow=a[i];
			for (int j=0; j<m; j++) t+=arow[j]*x[j];
			y[i]=t;
		}
	}
}