samer@0: /*
samer@0:  *	Copyright (c) 2000, 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.units;
samer@0: import  samer.core.*;
samer@0: import  samer.maths.*;
samer@0: import  samer.tools.*;
samer@0: 
samer@0: /** 
samer@0: 	A class for generating random vectors according
samer@0: 	to a particular generative model. If the output
samer@0: 	is y, then
samer@0: 		y = Bx + e
samer@0: 	where x is a vector of indepedent identitically
samer@0: 	distributed random variables, e is another vector of
samer@0: 	iid random variables, and B is an arbitrary matrix.
samer@0: 	The elements of x are the 'sources' and are drawn from
samer@0: 	the random number generator rnd. The elements of e
samer@0: 	are the 'noise' and are drawn from a different generator,
samer@0: 	which defaults to Gaussian.
samer@0:   */
samer@0: 
samer@0: public class NoisyLinearSource extends AnonymousTask
samer@0: {
samer@0: 	public 	VGenerator	src, noise;
samer@0: 	
samer@0: 	VVector				s;		// sources
samer@0: 	VVector				x;		// mixtures
samer@0: 	VVector				e;		// noise
samer@0: 	Matrix					A;		// mixing matrix
samer@0: 
samer@0: 	double []	xa, ea;
samer@0: 	Task			t1, t2;
samer@0: 
samer@0: 	public NoisyLinearSource( int m, int n)	throws Exception
samer@0: 	{
samer@0: 		// super("source");
samer@0: 
samer@0: 		// Shell.push(node);
samer@0: 		s   = new VVector("s",m);
samer@0: 		x   = new VVector("x",n);
samer@0: 		e   = new VVector("e",n);
samer@0: 		A   = new Matrix("A",n,m);
samer@0: 		A.identity();
samer@0: 
samer@0: 		src = new VGenerator("source");
samer@0: 		noise = new VGenerator("noise");
samer@0: 		// Shell.pop();
samer@0: 
samer@0: 		xa=s.array();
samer@0: 		ea=e.array();
samer@0: 		t1 = new MatrixTimesVector(x,A,s);
samer@0: 		t2 = new VectorPlusEqualsVector(x,e);
samer@0:  	}
samer@0: 
samer@0: 	public VVector	output() { return x; }
samer@0: 	public Matrix	getMixingMatrix() { return A; }
samer@0: 
samer@0: 	public void run() throws Exception { 
samer@0: 		src.next(xa); 
samer@0: 		noise.next(ea); 
samer@0: 		t1.run();
samer@0: 		t2.run();
samer@0: 		s.changed(); 
samer@0: 		x.changed(); 
samer@0: 		e.changed(); 
samer@0: 	}
samer@0: 
samer@0: 	public void dispose() 
samer@0: 	{
samer@0: 		src.dispose();
samer@0: 		noise.dispose();
samer@0: 		s.dispose();
samer@0: 		x.dispose();
samer@0: 		e.dispose();
samer@0: 		A.dispose();
samer@0: 		t1.dispose();
samer@0: 		t2.dispose();
samer@0: 		super.dispose();
samer@0: 	}
samer@0: }