ChooseFromArgs.java 

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package blog.distrib;

import java.util.*;
import Jama.Matrix;
import blog.*;
import common.Util;
CPD that takes a sequence of probabilities as parameters, and uses those probabilities to define a distribution over its arguments. The number of arguments must equal the number of probability parameters. Alternatively, a ChooseFromArgs CPD can be constructed with no parameters, in which case it expects a column vector of probabilities as its first argument and chooses from its remaining arguments. 


public class ChooseFromArgs extends AbstractCondProbDistrib {
Creates a ChooseFromArgs CPD with the given parameter vector. 


    public ChooseFromArgs(double[] probs) {
	this.probs = (double[]) probs.clone();
	expectProbsAsArg = false;
    }
Creates a new ChooseFromArgs distribution from the given parameter list. If the parameter list is empty, then the probability vector must be passed as an argument to this CPD. Otherwise, the parameter list should contain the probability vector as a sequence of Number objects. 


    public ChooseFromArgs(List params) {
	if (!params.isEmpty()) {
	    probs = new double[params.size()];
	    for (int i = 0; i < params.size(); ++i) {
		probs[i] = ((Number) params.get(i)).doubleValue();
	    }
	    expectProbsAsArg = false;
	}
    }
Returns the probability of the given child value conditioned on the given argument values. If this distribution was constructed with a probability vector, then the arguments are the possible values. Otherwise, the first argument should be a column vector of probabilities and the remaining arguments should be the possible values. specified at construction and the first argument is not a column vector of probabilities

Throws:  IllegalArgumentException if the probability vector was not 


    public double getProb(List args, Object childValue) {
	int firstPossibleValueIndex = ensureProbsInited(args);

	for (int i = 0; i < probs.length; ++i) {
	    if (childValue.equals(args.get(firstPossibleValueIndex + i))) {
		return probs[i];
	    }
	}
	return 0;
    }
Returns a value sampled according to this distribution. If this distribution was constructed with a probability vector, then the arguments are the possible values. Otherwise, the first argument should be a column vector of probabilities and the remaining arguments should be the possible values. specified at construction and the first argument is not a column vector of probabilities

Throws:  IllegalArgumentException if the probability vector was not 


    public Object sampleVal(List args, Type childType) {
	int firstPossibleValueIndex = ensureProbsInited(args);

	int i = Util.sampleWithProbs(probs);
	return args.get(firstPossibleValueIndex + i);
    }

    private int ensureProbsInited(List args) {
	int firstPossibleValueIndex = 0;
	if (expectProbsAsArg) {
	    if (args.isEmpty()) {
		throw new IllegalArgumentException
		    ("First argument to ChooseFromArgs CPD should be a "
		     + "column vector of probabilities, since the "
		     + "probabilities were not specified as CPD parameters.");
	    }
	    
	    if ((!(args.get(0) instanceof Matrix))
		    || (((Matrix) args.get(0)).getColumnDimension() != 1)) {
		throw new IllegalArgumentException
		    ("First argument to ChooseFromArgs CPD should be a column "
		     + "vector of probabilities, not: " + args.get(0));
	    }

	    Matrix m = (Matrix) args.get(0);
	    probs = new double[m.getRowDimension()];
	    for (int i = 0; i < probs.length; ++i) {
		probs[i] = m.get(i, 0);
	    }
	    firstPossibleValueIndex = 1;
	} 

	if (args.size() - firstPossibleValueIndex != probs.length) {
	    throw new IllegalArgumentException
		("ChooseFromArgs CPD with probability vector of length "
		 + probs.length + " should be given " + probs.length 
		 + " arguments to choose from, not "
		 + (args.size() - firstPossibleValueIndex));
	}

	return firstPossibleValueIndex;
    }

    private boolean expectProbsAsArg = true;
    private double[] probs = null;
}

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