/*
 * Copyright (c) 2005, Regents of the University of California
 * All rights reserved.
 * 
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.  
 *
 * * Neither the name of the University of California, Berkeley nor
 *   the names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior 
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 */

package blog.distrib;

import blog.*;
import Jama.*;
import java.util.*;
import common.Util;

public class UniformVector extends AbstractCondProbDistrib {

    

    public UniformVector( List params ){
	if ( (params.size() % 2) != 0) {
	    throw new IllegalArgumentException
		("Uniform vector distribution require an even number "
		 + "of parameters, not " + params.size() + ".");
	}
	for (int i = 0; i < params.size(); ++i) {
	    if (!(params.get(i) instanceof Number)) {
		throw new  IllegalArgumentException 
		    ("Parameter " + i + " to the uniform vector "
		     + "distribution must be of class Number, not " 
		     + params.get(i).getClass() + ".");
	    }
	}
	

	dim = params.size() / 2;
	mins = new double[dim];
	maxes = new double[dim];
	volume = 1;

	int paramIndex = 0;
	for (int i = 0; i < dim; ++i) {
	    mins[i] = ((Number) params.get(paramIndex++)).doubleValue();
	    maxes[i] = ((Number) params.get(paramIndex++)).doubleValue();
	    if (maxes[i] <= mins[i]) {
		throw new IllegalArgumentException
		    ("Specified maximum value " + maxes[i] 
		     + " must be greater than specified minimum " + mins[i]);
	    }
	    volume *= (maxes[i] - mins[i]);
	}
	
	densityInBox = 1 / volume;
	logDensityInBox = -Math.log(volume);
    }


    public double getProb( List args, Object value ) {
	Matrix x = checkArgs(args, value);
	return inBox(x) ? densityInBox : 0;
    }

    public double getLogProb(List args, Object value) {
	Matrix x = checkArgs(args, value);
	return inBox(x) ? logDensityInBox : Double.NEGATIVE_INFINITY;
    }

    public Object sampleVal( List args, Type childType ) {
	if (args.size() != 0) {
	    throw new IllegalArgumentException
		("Uniform vector distribution takes 0 arguments, "
		 + " not " + args.size() + ".");
	}

	Matrix sample = new Matrix(dim, 1);
	for (int i = 0; i < dim; ++i) {
	    sample.set(i, 0, mins[i] + (Util.random() * (maxes[i] - mins[i])));
	}
	return sample;
    }

    private Matrix checkArgs(List args, Object value) {
	if (args.size() != 0) {
	    throw new IllegalArgumentException
		("Uniform vector distribution takes 0 arguments, "
		 + " not " + args.size() + ".");
	}

	if(!((value instanceof Matrix) 
	     && (((Matrix) value).getColumnDimension() == 1))){
	    throw new IllegalArgumentException
		("The value passed to the uniform vector distribution's " 
		 + "getProb method must be a column vector.");
	}
	Matrix x = (Matrix) value;

	if (x.getRowDimension() != dim) {
	    throw new IllegalArgumentException
		("The vector passed to the uniform vector distribution's " 
		 + "getProb method must be " + dim
		 + "-dimensional, not " + x.getRowDimension()
		 + "-dimensional");
	}
	
	return x;
    }
    
    private boolean inBox(Matrix x) {
	for (int i = 0; i < dim; ++i) {
	    double val = x.get(i, 0);
	    if ((val < mins[i]) || (val > maxes[i])) {
		return false;
	    }
	}
	return true;
    }

    private int dim;
    private double[] mins;
    private double[] maxes;

    private double volume;
    private double densityInBox;
    private double logDensityInBox;
}

This file was generated on Tue Jun 08 17:53:48 PDT 2010 from file UniformVector.java
by the ilog.language.tools.Hilite Java tool written by Hassan Aït-Kaci