public SSA <SYMBOL> Collapse(Func <SSA <SYMBOL>, int, int, bool> statesAreEquivalent)
{
/* map state to equivalency class representative */
var stateMap = new Dictionary <int, int>();
foreach (int state in States)
{
foreach (int repr in stateMap.Values.Distinct()) // search equivalency classes
{
if (statesAreEquivalent(this, state, repr))
{
stateMap[state] = repr; // add to equivalency class
break;
}
}
if (!stateMap.ContainsKey(state)) // equivalency class not found
{
stateMap[state] = state; // new equivalency class
}
}
int initialState = stateMap[InitialState];
var finalStates = new Set <int>(FinalStates.Select(fs => stateMap[fs]));
var moves = new Set <Move <Predicate <SYMBOL> > >(Moves.Select(move =>
new Move <Predicate <SYMBOL> >(stateMap[move.SourceState], stateMap[move.TargetState], move.Label)
));
var alphabet = new Set <SYMBOL>(Alphabet);
return(new SSA <SYMBOL>(initialState, finalStates, moves, alphabet));
}
private Grammar MakeGrammarLeft()
{
IDictionary <char, TerminalSymbol> charTerminalMap = Alphabet.ToDictionary(c => c, c => new TerminalSymbol(c));
IDictionary <Label, NonTerminalSymbol> stateNonTerminalMap = States.ToDictionary(s => s, s => new NonTerminalSymbol(s));
NonTerminalSymbol target = Grammar.GetNewNonTerminal(stateNonTerminalMap.Values);
ISet <Rule> rules = new HashSet <Rule>();
foreach (Transition transition in Transitions)
{
Chain chain = new Chain(
EnumerateHelper.Sequence <Symbol>(
stateNonTerminalMap[transition.CurrentState], charTerminalMap[transition.Symbol]
)
);
rules.Add(new Rule(chain.AsSequence(), stateNonTerminalMap[transition.NextState]));
}
rules.Add(new Rule(Chain.Empty.AsSequence(), stateNonTerminalMap[InitialState]));
IEnumerable <Chain> chains = FinalStates.Select(fs => new Chain(stateNonTerminalMap[fs].AsSequence()));
rules.Add(new Rule(chains, target));
return(new Grammar(rules, target));
}
public StateMachine Reorganize(IDictionary <Label, Label> map)
{
if (map == null)
{
throw new ArgumentNullException(nameof(map));
}
Label initialState = map[InitialState];
IEnumerable <Label> finalStates = FinalStates.Select(fs => map[fs]);
IEnumerable <Transition> transitions = Transitions.Select(t => new Transition(map[t.CurrentState], t.Symbol, map[t.NextState]));
return(new StateMachine(initialState, finalStates, transitions));
}
/// <summary>
/// Normalizes state numbers to form sequence 0,1,2,... (initial state will be 0).
/// </summary>
public SST <SYMBOL> Normalize()
{
int id = 0;
Dictionary <int, int> stateDict = States
.OrderBy(state => state == InitialState ? -1 : Convert.ToInt32(IsFinalState(state)))
.ToDictionary(state => state, state => id++);
return(new SST <SYMBOL>(
stateDict[InitialState],
FinalStates.Select(state => stateDict[state]),
Moves.Select(move => new Move <Label <SYMBOL> >(
stateDict[move.SourceState], stateDict[move.TargetState], move.Label)),
Alphabet,
Name,
StateNames == null ? null : StateNames.ToDictionary(item => stateDict[item.Key], item => item.Value)
));
}
public StateMachine Minimize(
Action <MinimizingBeginPostReport> onBegin = null,
Action <MinimizingIterationPostReport> onIterate = null,
Action <bool> onEnd = null)
{
ILookup <Label, Transition> transitionsByCurrentState = Transitions.ToLookup(transition => transition.CurrentState);
ISet <Label> nonFinalStates = new SortedSet <Label>(States);
nonFinalStates.ExceptWith(FinalStates);
SetsOfEquivalence setsOfEquivalence = new SetsOfEquivalence(
EnumerateHelper.Sequence(
new SetOfEquivalence(nonFinalStates),
new SetOfEquivalence(FinalStates)
)
);
int i = 0;
if (onBegin != null)
{
onBegin(new MinimizingBeginPostReport(setsOfEquivalence, i));
}
bool changed;
do
{
changed = false;
i++;
List <SetOfEquivalence> buildingSetsOfEquivalence = new List <SetOfEquivalence>();
List <SetOfEquivalenceTransition> setOfEquivalenceTransitions = new List <SetOfEquivalenceTransition>();
IDictionary <Label, int> statesMap = GetStatesMap(setsOfEquivalence);
foreach (SetOfEquivalence setOfEquivalence in setsOfEquivalence)
{
IDictionary <ClassOfEquivalenceSet, ISet <Label> > classEquivalenceSetMap = new Dictionary <ClassOfEquivalenceSet, ISet <Label> >();
foreach (Label state in setOfEquivalence)
{
IDictionary <int, ISet <char> > groupMap = new Dictionary <int, ISet <char> >();
foreach (Transition transition in transitionsByCurrentState[state])
{
int groupNum = statesMap[transition.NextState];
ISet <char> equality;
if (groupMap.ContainsKey(groupNum))
{
equality = groupMap[groupNum];
}
else
{
groupMap[groupNum] = equality = new HashSet <char>();
}
equality.Add(transition.Symbol);
}
ClassOfEquivalenceSet classOfEquivalenceSet = new ClassOfEquivalenceSet(groupMap.Select(item => new ClassOfEquivalence(item.Key, item.Value)));
ISet <Label> states;
if (classEquivalenceSetMap.ContainsKey(classOfEquivalenceSet))
{
states = classEquivalenceSetMap[classOfEquivalenceSet];
}
else
{
classEquivalenceSetMap[classOfEquivalenceSet] = states = new HashSet <Label>();
}
states.Add(state);
}
foreach (KeyValuePair <ClassOfEquivalenceSet, ISet <Label> > entry in classEquivalenceSetMap)
{
SetOfEquivalence set = new SetOfEquivalence(entry.Value, entry.Key.Select(c => new SetOfEquivalenceTransition(c.Symbols, c.SetNum)));
buildingSetsOfEquivalence.Add(set);
}
}
SetsOfEquivalence nextSetsOfEquivalence = new SetsOfEquivalence(buildingSetsOfEquivalence);
changed = setsOfEquivalence != nextSetsOfEquivalence;
setsOfEquivalence = nextSetsOfEquivalence;
if (onIterate != null)
{
onIterate(new MinimizingIterationPostReport(setsOfEquivalence, i, !changed));
}
} while (changed);
if (onEnd != null)
{
onEnd(setsOfEquivalence.Count != States.Count);
}
if (setsOfEquivalence.Count == States.Count)
{
return(this);
}
IDictionary <Label, Label> newStatesMap = GetOldNewStatesMap(setsOfEquivalence);
ISet <Transition> transitions = Transitions.Select(item => new Transition(newStatesMap[item.CurrentState], item.Symbol, newStatesMap[item.NextState])).ToHashSet();
ISet <Label> finalStates = FinalStates.Select(item => newStatesMap[item]).ToHashSet();
Label initialState = newStatesMap[InitialState];
return(new StateMachine(initialState, finalStates, transitions));
}
