public override bool Equals(object obj)
{
LabelAlgebra <SYMBOL> algebra = obj as LabelAlgebra <SYMBOL>;
if (obj != null)
{
return(this.pa.Equals(algebra.pa));
}
return(false);
}
/// <summary>
/// Compose transducers T1 and T2, resulting in transducer equivalent to applying T2 after T1.
/// </summary>
public static SST <SYMBOL> Compose(SST <SYMBOL> tau1, SST <SYMBOL> tau2)
{
if (tau1.Algebra != tau2.Algebra)
{
throw SSTException.IncompatibleAlphabets();
}
LabelAlgebra <SYMBOL> algebra = tau1.Algebra;
var stack = new Stack <Tuple <int, int> >();
var finalStates = new List <int>();
var moves = new List <Move <Label <SYMBOL> > >();
var stateDict = new Dictionary <Tuple <int, int>, int>();
int id = 0;
var init = new Tuple <int, int>(tau1.InitialState, tau2.InitialState);
stateDict[init] = id++;
stack.Push(init);
while (stack.Count > 0)
{
Tuple <int, int> sourcePair = stack.Pop();
int state1 = sourcePair.Item1;
int state2 = sourcePair.Item2;
foreach (Move <Label <SYMBOL> > move1 in tau1.GetMovesFrom(state1))
{
foreach (Move <Label <SYMBOL> > move2 in tau2.GetMovesFrom(state2))
{
Label <SYMBOL> newLabel = algebra.Combine(move1.Label, move2.Label);
if (!algebra.IsSatisfiable(newLabel))
{
continue;
}
var targetPair = new Tuple <int, int>(move1.TargetState, move2.TargetState);
int targetState;
if (!stateDict.TryGetValue(targetPair, out targetState))
{
stateDict[targetPair] = targetState = id++;
stack.Push(targetPair);
if (tau1.IsFinalState(move1.TargetState) && tau2.IsFinalState(move2.TargetState))
{
finalStates.Add(targetState);
}
}
moves.Add(new Move <Label <SYMBOL> >(stateDict[sourcePair], targetState, newLabel));
}
}
}
return(new SST <SYMBOL>(0, finalStates, moves));
}