samer@0: package samer.mds;
samer@0: 
samer@0: // import samer.core.*;
samer@0: import samer.maths.*;
samer@0: import samer.tools.*;
samer@0: 
samer@0: /**
samer@0: 	Transfer distances directly from a distance matrix to an MDS
samer@0: 	object's distance vector.
samer@0: */
samer@0: public class DistanceTask extends AnonymousTask
samer@0: {
samer@0: 	int		N;
samer@0: 	double [] d;				// linear array of distances
samer@0: 	double [][] _D;			// matrix of source data
samer@0: 		
samer@0: 	/** link each object to all the others using distances in matrix, returns a task
samer@0: 		that can be used to refresh distances from original matrix */
samer@0: 	public DistanceTask(MDSBase mds, Matrix D) {
samer@0: 		N = D.getRowDimension();
samer@0: 		
samer@0: 		d=new double[N*(N - 1)/2];
samer@0: 		_D=D.getArray();
samer@0: 		
samer@0: 		mds.clearLinks(d);
samer@0: 		for (int k=0, i=0; i<N; i++) 
samer@0: 			for (int j=i+1; j<N; j++) mds.setLink(k++,i,j);
samer@0: 		
samer@0: 		run();
samer@0: 	}
samer@0: 
samer@0: 	public Vec getDistances() { return new Vec.ForArray(d); }
samer@0: 	public void run() {
samer@0: 		for (int k=0, i=0; i<N; i++) {
samer@0: 			double [] Drow=_D[i];
samer@0: 			for (int j=i+1; j<N; j++) d[k++]=Drow[j];
samer@0: 		}
samer@0: 	}
samer@0: }