/** change the parameter and return the hastings ratio. */
public double doOperation() throws OperatorFailedException {
double[] mean = sccs.getMode();
double[] currentValue = parameter.getParameterValues();
double[] newValue = new double[dim];
Set<Integer> updateSet = new HashSet<Integer>();
if (setSizeMean != -1.0) {
final int listLength = Poisson.nextPoisson(setSizeMean);
while (updateSet.size() < listLength) {
int newInt = MathUtils.nextInt(parameter.getDimension());
if (!updateSet.contains(newInt)) {
updateSet.add(newInt);
}
}
} else {
for (int i = 0; i < dim; ++i) {
updateSet.add(i);
}
}
double logq = 0;
for (Integer i : updateSet) {
newValue[i] = mean[i] + scaleFactor * MathUtils.nextGaussian();
if (UPDATE_ALL) {
parameter.setParameterValueQuietly(i, newValue[i]);
} else {
parameter.setParameterValue(i, newValue[i]);
}
logq +=
(NormalDistribution.logPdf(currentValue[i], mean[i], scaleFactor)
- NormalDistribution.logPdf(newValue[i], mean[i], scaleFactor));
}
// for (Integer i : updateSet) {
// parameter.setParameterValueQuietly(i, newValue[i]);
// }
if (UPDATE_ALL) {
parameter.setParameterValueNotifyChangedAll(0, parameter.getParameterValue(0));
}
return logq;
}
