/*
* ValuesPoolSwapOperator.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.inference.operators;
import dr.inference.model.ValuesPool;
import dr.inference.model.Variable;
import dr.inferencexml.operators.ValuesPoolSwapOperatorParser;
import dr.math.MathUtils;
/**
* @author Joseph Heled
* Date: 8/09/2009
*/
public class ValuesPoolSwapOperator extends SimpleMCMCOperator {
private final ValuesPool pool;
public ValuesPoolSwapOperator(ValuesPool pool) {
this.pool = pool;
}
public String getOperatorName() {
return ValuesPoolSwapOperatorParser.VALUESPOOL_OPERATOR + "(" + pool.getModelName() + ")";
}
public double doOperation() {
final Variable<Double> selector = pool.getSelector();
final int[] ints = SelectorOperator.intVals(selector);
int[] c = SelectorOperator.counts_used_m2(ints);
int n = 0;
for(int k = 0; k < c.length-1; ++k) {
if( c[k] == c[k+1] ) {
++n;
}
}
if( n == 0 ) {
throw new RuntimeException("No moves");
}
int j = MathUtils.nextInt(n);
int p;
for(p = 0; p < c.length-1; ++p) {
if( c[p] == c[p+1] ) {
if( j == 0 ) {
break;
}
j -= 1;
}
}
int ip = -1, ip1 = -1;
// exchange p's and p+1's
int count = c[p];
while( count > 0 ) {
while( ints[++ip] != p );
while( ints[++ip1] != p+1 );
selector.setValue(ip, (double)(p+1));
selector.setValue(ip1, (double)(p));
--count;
}
final Variable<Double> vals = pool.getPool();
final Double vp = vals.getValue(p);
final Double vp1 = vals.getValue(p+1);
vals.setValue(p, vp1);
vals.setValue(p+1, vp);
return 0;
}
public String getPerformanceSuggestion() {
return null;
}
}