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

Initial Mercurial check in.

/*
 *	Copyright (c) 2002, 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;

public class SparseMatrix {
	int			max, n;	// number of elements
	int[]		i, j;			// element indices
	double[]	x;			// element values

	public SparseMatrix(String name) {}
	public SparseMatrix(String name, SparseMatrix mask) {
		n=mask.n;
		i=(int[])mask.i.clone();
		j=(int[])mask.j.clone();
		x=new double[n];
	}

	/** allocate space for E elements and remove all elements */
	public void allocate(int E) {
		this.max=E; 	n=0;
		i=new int[E];
		j=new int[E];
		x=new double[E];
	}

	/** add a new element to list. (Must be room for it) */
	public void addElement( int i, int j, double x) {
		this.i[n]=i;
		this.j[n]=j;
		this.x[n]=x;
		n++;
	}

	public void times(double [] out, double [] in) {
		Mathx.zero(out);
		for (int k=0; k<n; k++) {
			out[i[k]]+=x[k]*in[j[k]];
		}
	}

	public void transposeTimes(double [] out, double [] in) {
		Mathx.zero(out);
		for (int k=0; k<n; k++) {
			out[j[k]]+=x[k]*in[i[k]];
		}
	}

	public void zero() { Mathx.zero(x); }

	public void addOuterProduct(double[] a, double[] b) {
		for (int k=0; k<n; k++) x[k] += a[i[k]]*b[j[k]];
	}

	public void icaUpdate(SparseMatrix GW, double eta, double batch) {
		double[] dx=GW.x;
		Mathx.mul(dx,1/batch);
		for (int k=0; k<n; k++) x[k] += eta*(dx[k]-x[k]);
	}

	public void identity() { for (int k=0; k<n; k++) x[k] = (i[k]==j[k]) ? 1 : 0; }
	public void getMatrix(Matrix A) {
		A.zero();
		for (int k=0; k<n; k++) A.set(i[k],j[k],x[k]);
	}
		
	public void changed() {}
	public void dispose() {}
}