/*
* UniformPartitionLikelihood.java
*
* Copyright (c) 2002-2015 Alexei Drummond, Andrew Rambaut and Marc Suchard
*
* This file is part of BEAST.
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership and licensing.
*
* BEAST is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* BEAST is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with BEAST; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
package dr.evomodel.arg;
import dr.inference.model.Likelihood;
import dr.inference.model.Model;
import dr.inference.model.Variable;
import dr.inference.model.Variable.ChangeType;
import dr.math.MathUtils;
import dr.xml.*;
public class UniformPartitionLikelihood extends ARGPartitionLikelihood implements Likelihood {
public static final String UNIFORM_PARTITION_LIKELIHOOD = "uniformPartitionLikelihood";
private double logStateCount;
private boolean isRecombination;
public UniformPartitionLikelihood(String id, ARGModel arg) {
super(id, arg);
isRecombination = arg.isRecombinationPartitionType();
int numberOfPartitionsMinusOne = getNumberOfPartitionsMinusOne();
if (arg.isRecombinationPartitionType()) {
//For example, if we have five partitions, we can have the following
// 0 1 1 1 1
// 0 0 1 1 1 <-- Equates to four possibilities
// 0 0 0 1 1
// 0 0 0 0 1
logStateCount = Math.log(numberOfPartitionsMinusOne);
} else {
//You basically choose a subset from all possible subset of the final four
//there are 2^numberOfPartitionsMinusOne of these
//
//Except! you cannot choose the empty set.
double rValue = Math.pow(2.0, numberOfPartitionsMinusOne) - 1;
logStateCount = Math.log(rValue);
}
}
public double[] generatePartition() {
if (isRecombination) {
return generateRecombinationPartition();
}
return generateReassortmentPartition();
}
private double[] generateRecombinationPartition() {
int numberOfPartitionsMinusOne = getNumberOfPartitionsMinusOne();
int cut = MathUtils.nextInt(numberOfPartitionsMinusOne);
int leftValue = 0; //At one time, these values could switch.
int rightValue = 1;
double[] partition = new double[numberOfPartitionsMinusOne + 1];
for (int i = 0; i < cut + 1; i++)
partition[i] = leftValue;
for (int i = cut + 1; i < partition.length; i++)
partition[i] = rightValue;
return partition;
}
public static double arraySum(double[] x) {
double a = 0;
for (double b : x)
a += b;
return a;
}
private double[] generateReassortmentPartition() {
int numberOfPartitions = getNumberOfPartitionsMinusOne() + 1;
double[] partition = new double[numberOfPartitions];
while (arraySum(partition) == 0) {
for (int i = 1; i < partition.length; i++) {
if (MathUtils.nextBoolean()) {
partition[i] = 1.0;
} else {
partition[i] = 0.0;
}
}
}
partition[0] = 0.0;
return partition;
}
public double getLogLikelihood(double[] partition) {
return -logStateCount;
}
public static XMLObjectParser PARSER = new AbstractXMLObjectParser() {
public String getParserDescription() {
return null;
}
public Class getReturnType() {
return UniformPartitionLikelihood.class;
}
public XMLSyntaxRule[] getSyntaxRules() {
return new XMLSyntaxRule[]{
new ElementRule(ARGModel.class, false),
};
}
public Object parseXMLObject(XMLObject xo) throws XMLParseException {
ARGModel arg = (ARGModel) xo.getChild(ARGModel.class);
String id = "";
if (xo.hasId())
id = xo.getId();
return new UniformPartitionLikelihood(id, arg);
}
public String getParserName() {
return UNIFORM_PARTITION_LIKELIHOOD;
}
};
protected void acceptState() {
//nothing to do
}
protected void handleModelChangedEvent(Model model, Object object, int index) {
//has no submodels
}
protected void handleVariableChangedEvent(Variable variable, int index,
ChangeType type) {
//has no parameters
}
protected void restoreState() {
//nothing to restore
}
protected void storeState() {
// nothing to store
}
}