/// <summary> /// Find the deadlock state. This state can be reached by a terminate event. /// Later termination transition is removed from the transition to finding path /// [ REFS: , DEREFS: ] /// </summary> /// <param name="transitions"></param> /// <param name="model"></param> /// <returns></returns> public static CUDDNode GetDeadlockDD(List<CUDDNode> transitions, Model model) { CUDDNode result = CUDD.Constant(1); //result contains state not having not tick outgoing transition foreach (CUDDNode transition in transitions) { CUDD.Ref(transition); CUDDNode notTickTrans = CUDD.Function.And(transition, CUDD.Function.Not(TimeBehaviors.GetTickTransEncoding(model))); //having not tick outgoing transition CUDDNode notDeadlockState = CUDD.Abstract.ThereExists(notTickTrans, model.AllColVars); CUDDNode deadlockState = CUDD.Function.Not(notDeadlockState); result = CUDD.Function.And(result, deadlockState); } CUDD.Ref(transitions); List<CUDDNode> tickTrans = CUDD.Function.And(transitions, TimeBehaviors.GetTickTransEncoding(model)); CUDD.Ref(tickTrans); CUDDNode stateHasTickTrans = CUDD.Function.Or(CUDD.Abstract.ThereExists(tickTrans, model.AllColVars)); List<int> eventIndex = model.GetEventIndex(); for (int i = 0; i < model.GetNumberOfVars(); i++) { if(!eventIndex.Contains(i)) { CUDD.Ref(model.varIdentities[i]); tickTrans = CUDD.Function.And(tickTrans, model.varIdentities[i]); } } CUDDNode stateHasLoopTick = CUDD.Function.Or(CUDD.Abstract.ThereExists(tickTrans, model.AllColVars)); //Deadlock state: not having not tick transition and if has tick, then it must loop tick CUDD.Ref(result); result = CUDD.Function.Or(CUDD.Function.And(result, CUDD.Function.Not(stateHasTickTrans)), CUDD.Function.And(result, stateHasLoopTick)); return result; }