/*
 * Copyright (c) 2005, 2006, Regents of the University of California
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * 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
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package blog.distrib;

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

public class CharDistrib extends AbstractCondProbDistrib { 
    

    public CharDistrib(char[] enumChars, double uniformWeight) {
	this.enumChars = enumChars;
	initCharIndices();
	enumDistrib = new Categorical(enumChars.length);
	
	if ((uniformWeight < 0) || (uniformWeight > 1)) {
	    throw new IllegalArgumentException("uniformWeight must be between "
					       + "0 and 1.");
	}
	this.uniformWeight = uniformWeight;
    }

    

    public CharDistrib(char[] enumChars, double[] pi, double uniformWeight) {
	this.enumChars = enumChars;
	initCharIndices();
	enumDistrib = new Categorical(pi);
		
	if ((uniformWeight < 0) || (uniformWeight > 1)) {
	    throw new IllegalArgumentException("uniformWeight must be between "
					       + "0 and 1.");
	}
	this.uniformWeight = uniformWeight;
    }

    

    public CharDistrib(List params) {
	if (params.size() != 3) {
	    throw new IllegalArgumentException
		("CharDistrib expects three parameters: string of enumerated "
		 + "characters, probability vector, and weight on uniform "
		 + "distribution.");
	}

	if (params.get(0) instanceof String) {
	    enumChars = ((String) params.get(0)).toCharArray();
	    initCharIndices();
	} else {
	    throw new IllegalArgumentException
		("First parameter to CharDistrib must be a String.");
	}

	if (params.get(1) instanceof Matrix) {
	    Matrix pi = (Matrix) params.get(1);
	    if ((pi.getRowDimension() == 1) 
		    && (pi.getColumnDimension() == enumChars.length)) {
		enumDistrib = new Categorical(pi.getRowPackedCopy());
	    } else if ((pi.getRowDimension() == enumChars.length)
		       && (pi.getColumnDimension() == 1)) {
		enumDistrib = new Categorical(pi.getColumnPackedCopy());
	    } else {
		throw new IllegalArgumentException
		    ("Probability vector must be either 1xN or Nx1, where "
		     + "N is length of enumerated character string.");
	    }
	} else {
	    throw new IllegalArgumentException
		("Second parameter to CharDistrib must be a vector "
		 + "(represented as a Matrix object).");
	}

	if (params.get(2) instanceof Number) {
	    uniformWeight = ((Number) params.get(2)).doubleValue();
	    if ((uniformWeight < 0) || (uniformWeight > 1)) {
		throw new IllegalArgumentException
		    ("Weight on uniform distrib must be between 0 and 1.");
	    }
	} else {
	    throw new IllegalArgumentException
		("Third parameter to CharDistrib must be a Number.");
	}
    }

    

    public double getProb(char c) {
	double prob = uniformWeight / Character.MAX_VALUE;
	int index = getCharIndex(c);
	if (index != -1) {
	    prob += ((1 - uniformWeight) * enumDistrib.getProb(index));
	}
	return prob;
    }

    

    public double getProb(List args, Object childValue) {
	if (!args.isEmpty()) {
	    throw new IllegalArgumentException
		("CharDistrib expects no arguments.");
	}

	if (childValue instanceof Character) {
	    return getProb(((Character) childValue).charValue());
	} else {
	    throw new IllegalArgumentException
		("CharDistrib defines distribution over objects of class "
		 + "Character, not " + childValue.getClass());
	}
    }

    

    public double getLogProb(char c) {
	return Math.log(getProb(c));
    }

    

    public char sampleVal() {
	if (Util.random() < uniformWeight) {
	    return (char) Util.randInt(Character.MAX_VALUE);
	}
	int index = enumDistrib.sampleVal();
	return enumChars[index];
    }

    

    public Object sampleVal(List args, Type childType) {
	if (!args.isEmpty()) {
	    throw new IllegalArgumentException
		("CharDistrib expects no arguments.");
	}
	
	return new Character(sampleVal());
    }

    void initCharIndices() {
	int maxChar = 0;
	for (int i = 0; i < enumChars.length; i++) {
	    if (enumChars[i] > maxChar) {
		maxChar = enumChars[i];
	    }
	}

	charIndices = new int[maxChar + 1];
	for (int i = 0; i < charIndices.length; i++) {
	    charIndices[i] = -1;
	}

	for (int i = 0; i < enumChars.length; i++) {
	    charIndices[enumChars[i]] = i;
	}
    }

    int getCharIndex(char c) {
	if (c >= charIndices.length) {
	    return -1;
	}
	return charIndices[c];
    }

    char[] enumChars;
    int[] charIndices;
    Categorical enumDistrib;
    double uniformWeight;
}

This file was generated on Tue Jun 08 17:53:47 PDT 2010 from file CharDistrib.java
by the ilog.language.tools.Hilite Java tool written by Hassan Aït-Kaci