private static SamplerDouble createSamplerForRewardProperty(ExpressionReward expr, ModulesFile mf)
throws PrismException {
// Extract reward structure index
Object rs = expr.getRewardStructIndex();
int rsi = -1;
if (mf.getNumRewardStructs() == 0) throw new PrismException("Model has no rewards specified");
if (rs == null) {
rsi = 0;
} else if (rs instanceof Expression) {
rsi = ((Expression) rs).evaluateInt();
rs = new Integer(rsi); // for better error reporting below
rsi = (rsi < 1 || rsi > mf.getNumRewardStructs()) ? -1 : rsi - 1;
} else if (rs instanceof String) {
rsi = mf.getRewardStructIndex((String) rs);
}
if (rsi == -1) throw new PrismException("Invalid reward structure index \"" + rs + "\"");
// Construct sampler based on type
ExpressionTemporal exprTemp = (ExpressionTemporal) expr.getExpression();
switch (exprTemp.getOperator()) {
case ExpressionTemporal.R_C:
if (mf.getModelType().continuousTime()) {
// Continuous-time cumulative reward
return new SamplerRewardCumulCont(exprTemp, rsi);
} else {
// Discrete-time cumulative reward
return new SamplerRewardCumulDisc(exprTemp, rsi);
}
case ExpressionTemporal.R_I:
if (mf.getModelType().continuousTime()) {
// Continuous-time instantaneous reward
return new SamplerRewardInstCont(exprTemp, rsi);
} else {
// Discrete-time instantaneous reward
return new SamplerRewardInstDisc(exprTemp, rsi);
}
case ExpressionTemporal.P_F:
// reachability reward
return new SamplerRewardReach(exprTemp, rsi);
}
throw new PrismException("Can't create sampler for property \"" + expr + "\"");
}
