samer@0: /*
samer@0:  *	Copyright (c) 2002, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS iS and WITHOUT ANY WARRANTY;
samer@0:  *	without even the implied warranty of MERCHANTABILITY or
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package samer.maths;
samer@0: 
samer@0: public class SparseMatrix {
samer@0: 	int			max, n;	// number of elements
samer@0: 	int[]		i, j;			// element indices
samer@0: 	double[]	x;			// element values
samer@0: 
samer@0: 	public SparseMatrix(String name) {}
samer@0: 	public SparseMatrix(String name, SparseMatrix mask) {
samer@0: 		n=mask.n;
samer@0: 		i=(int[])mask.i.clone();
samer@0: 		j=(int[])mask.j.clone();
samer@0: 		x=new double[n];
samer@0: 	}
samer@0: 
samer@0: 	/** allocate space for E elements and remove all elements */
samer@0: 	public void allocate(int E) {
samer@0: 		this.max=E; 	n=0;
samer@0: 		i=new int[E];
samer@0: 		j=new int[E];
samer@0: 		x=new double[E];
samer@0: 	}
samer@0: 
samer@0: 	/** add a new element to list. (Must be room for it) */
samer@0: 	public void addElement( int i, int j, double x) {
samer@0: 		this.i[n]=i;
samer@0: 		this.j[n]=j;
samer@0: 		this.x[n]=x;
samer@0: 		n++;
samer@0: 	}
samer@0: 
samer@0: 	public void times(double [] out, double [] in) {
samer@0: 		Mathx.zero(out);
samer@0: 		for (int k=0; k<n; k++) {
samer@0: 			out[i[k]]+=x[k]*in[j[k]];
samer@0: 		}
samer@0: 	}
samer@0: 
samer@0: 	public void transposeTimes(double [] out, double [] in) {
samer@0: 		Mathx.zero(out);
samer@0: 		for (int k=0; k<n; k++) {
samer@0: 			out[j[k]]+=x[k]*in[i[k]];
samer@0: 		}
samer@0: 	}
samer@0: 
samer@0: 	public void zero() { Mathx.zero(x); }
samer@0: 
samer@0: 	public void addOuterProduct(double[] a, double[] b) {
samer@0: 		for (int k=0; k<n; k++) x[k] += a[i[k]]*b[j[k]];
samer@0: 	}
samer@0: 
samer@0: 	public void icaUpdate(SparseMatrix GW, double eta, double batch) {
samer@0: 		double[] dx=GW.x;
samer@0: 		Mathx.mul(dx,1/batch);
samer@0: 		for (int k=0; k<n; k++) x[k] += eta*(dx[k]-x[k]);
samer@0: 	}
samer@0: 
samer@0: 	public void identity() { for (int k=0; k<n; k++) x[k] = (i[k]==j[k]) ? 1 : 0; }
samer@0: 	public void getMatrix(Matrix A) {
samer@0: 		A.zero();
samer@0: 		for (int k=0; k<n; k++) A.set(i[k],j[k],x[k]);
samer@0: 	}
samer@0: 		
samer@0: 	public void changed() {}
samer@0: 	public void dispose() {}
samer@0: }