view src/samer/models/AlignedGaussian.java @ 5:b67a33c44de7

Remove some crap, etc

/*
 *	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.models;

import samer.core.*;
import samer.core.types.*;
import samer.maths.*;
import samer.maths.opt.*;
import samer.tools.*;

/**
	Differential scaler: scales and offsets each element of a vector
	independently aiming to match a given prior model. This is
	like ICA using a diagonal weight matrix, with a 'zero-mean'
	normalisation built in, though it doesn't actually the mean to
	do this, but some statistic based on the prior model.
*/

public class AlignedGaussian extends AnonymousTask implements Model
{
	private int			n;
	private Vec			x;
	private VVector	s;
	private VVector	w;		// vector of multipliers
	private VDouble	E;
	private VDouble	logA;

	double []		_x, _s, _g, _w, _m, phi;

	public AlignedGaussian( Vec input) { this(input.size()); setInput(input); }
	public AlignedGaussian( int N)
	{
		n = N;

		x = null;
		w = new VVector("w",n);		w.addSaver();
		s = new VVector("s",n);
		E = new VDouble("E");
		logA = new VDouble("log|A|",0);
		

		_s = s.array();
		_w = w.array();
		_g = new double[n];
		phi = null;
		reset();
	}

	public int getSize() { return n; }
	public VVector output() { return s; }
	public VVector weights() { return w; }
	public void setInput(Vec in) { x=in; _x=x.array(); }
	public void reset() { reset(1.0); }
	public void reset(double k) {
		Mathx.setAll(_w,k); w.changed();
		logA.set(-sumlog(_w));
	}

	public String toString() { return "AlignedGaussian("+x+")"; }
	private static double sumlog(double [] x) {
		double S=0;
		for (int i=0; i<x.length; i++) S += Math.log(x[i]);
		return S;
	}

	public void dispose()
	{
		logA.dispose();
		w.dispose();
		s.dispose();
		super.dispose();
	}

	public void infer() { Mathx.mul(_s,_x,_w); s.changed(); }
	public void compute() { 
		Mathx.mul(_g,_s,_w); 
		E.set(0.5*Mathx.norm2(_s)+logA.value);
	}

	public double	getEnergy() { return E.value; }
	public double [] getGradient() { return _g; }

	public Functionx functionx() {
		return new Functionx() {
			double [] s=new double[n];

			public void dispose() {}
			public void evaluate(Datum P) { P.f=evaluate(P.x,P.g); }
			public double evaluate(double [] x, double [] g) {
				Mathx.mul(s,x,_w);
				Mathx.mul(g,s,_w);
				return 0.5*Mathx.norm2(s); // +logA.value;
			}
		};
	}

	public void starting() { logA.set(-sumlog(_w)); }
	public void stopping() {}
	public void run() { infer(); compute(); }
}