/// <summary>
/// Evaluates the reachable state space of a transition system given a initial state.
/// </summary>
/// <param name="I">The Bdd representing the initial state of the system.</param>
/// <param name="T">The Bdd representing all possible transition in the system.</param>
/// <param name="bpl">A list of variable pairs that represent pre- and post-states.</param>
/// <returns>The Bdd representing the reachable state space.</returns>
public static Bdd ReachableStates(Bdd I, Bdd T, BddPairList bpl)
{
Bdd Rp;
Bdd R = new Bdd(false);
do
{
Rp = R;
R = I | ExecuteTransition(R, T, bpl);
}while (!R.Equals(Rp));
return(R);
}
/// <summary>
/// Evaluates the number of transitions it takes to reach a state from a given initial
/// state in a transition system.
/// </summary>
/// <param name="I">The Bdd representing the initial state of the system.</param>
/// <param name="E">The state that what to be reached.</param>
/// <param name="T">The Bdd representing all possible transition in the system.</param>
/// <param name="bpl">A list of variable pairs that represent pre- and post-states.</param>
/// <returns>Number of transitions needed. -1 if no trace exists.</returns>
public static int Tracelength(Bdd I, Bdd E, Bdd T, BddPairList bpl)
{
int tracelength = 0;
Bdd Rp, test;
Bdd R = I;
do
{
Rp = R;
R = I | ExecuteTransition(R, T, bpl);
test = E >= R;
if (R.Equals(Rp) & test.U != Kernel.bddtrue)
{
return(-1);
}
tracelength++;
}while (test.U != Kernel.bddtrue);
return(tracelength);
}