/**
* Determine which locations in the PTA satisfy a (Boolean) expression. Note: This is rather
* inefficiently at the moment. TODO: potentially use explicit.StateMC on dummy model eventually
*/
private BitSet checkLocationExpression(Expression expr) throws PrismException {
int i, n;
BitSet res;
// Labels - expand and recurse
// (note: currently not used - these are expanded earlier)
if (expr instanceof ExpressionLabel) {
ExpressionLabel exprLabel = (ExpressionLabel) expr;
if (exprLabel.getName().equals("deadlock"))
throw new PrismException("The \"deadlock\" label is not yet supported for PTAs");
if (exprLabel.getName().equals("init"))
throw new PrismException("The \"init\" label is not yet supported for PTAs");
i = labelList.getLabelIndex(exprLabel.getName());
if (i == -1)
throw new PrismException("Unknown label \"" + exprLabel.getName() + "\" in property");
// Check recursively
return checkLocationExpression(labelList.getLabel(i));
}
// Other expressions...
else {
List<Object> states;
// Object[] state;
states = pta.getLocationNameList();
n = states.size();
res = new BitSet(n);
for (i = 0; i < n; i++) {
// state = (Object[])states.get(i);
State state = (State) states.get(i);
if (expr.evaluateBoolean(state, nonClockVarMap)) {
res.set(i);
}
}
}
return res;
}
/** Build a time bounded reachability query into a PTA; return the new target location set. */
private BitSet buildTimeBoundIntoPta(
PTA pta, BitSet targetLocs, int timeBound, boolean timeBoundStrict) {
String timerClock = null;
int timerClockIndex, numLocs, newTargetLoc;
String newTargetLocString;
List<Transition> trNewList;
Transition trNew;
BitSet targetLocsNew;
boolean toTarget;
int i;
// Add a timer clock
timerClock = "time";
while (pta.getClockIndex(timerClock) != -1) timerClock += "_";
timerClockIndex = pta.addClock(timerClock);
// Add a new target location
numLocs = pta.getNumLocations();
newTargetLocString = "target";
while (pta.getLocationIndex(newTargetLocString) != -1) newTargetLocString += "_";
newTargetLoc = pta.addLocation(newTargetLocString);
// Go through old (on-target) locations
for (i = 0; i < numLocs; i++) {
trNewList = new ArrayList<Transition>();
for (Transition tr : pta.getTransitions(i)) {
// See if the transition can go to a target location
toTarget = false;
for (Edge e : tr.getEdges()) {
if (targetLocs.get(e.getDestination())) {
toTarget = true;
break;
}
}
// Copy transition, modify edges going to target and add guard
if (toTarget) {
trNew = new Transition(tr);
for (Edge e : trNew.getEdges()) {
if (targetLocs.get(e.getDestination())) {
e.setDestination(newTargetLoc);
}
}
if (timeBoundStrict)
trNew.addGuardConstraint(Constraint.buildLt(timerClockIndex, timeBound));
else trNew.addGuardConstraint(Constraint.buildLeq(timerClockIndex, timeBound));
trNewList.add(trNew);
// Modify guard of copied transition
if (timeBoundStrict)
tr.addGuardConstraint(Constraint.buildGeq(timerClockIndex, timeBound));
else tr.addGuardConstraint(Constraint.buildGt(timerClockIndex, timeBound));
}
}
// Add new transitions to PTA
for (Transition tr : trNewList) {
pta.addTransition(tr);
}
}
// Re-generate set of target locations
targetLocsNew = new BitSet(pta.getNumLocations());
targetLocsNew.set(newTargetLoc);
return targetLocsNew;
}