@Override
public double doOperation() throws OperatorFailedException {
apspnet.beginNetworkEdit();
double b = (1.0 - scalingFactor) * (1.0 - scalingFactor) / scalingFactor;
double c = scalingFactor / (1.0 - scalingFactor);
double y = MathUtils.nextDouble();
double s = b * (y + c) * (y + c);
int i = MathUtils.nextInt(apspnet.getNumberOfTetraTrees());
apspnet.setOneHybPopValue(i, s * apspnet.getOneHybPopValue(i));
apspnet.endNetworkEdit();
return 0.0; // this way of scaling, with proposal proportional to x^-(1/2) has hastings ratio 1
}
