internal static Automaton PopulateDFAWithXAndEpsilonTransitionsNaive(this Automaton automaton)
{
bool changes = true;
while (changes)
{
changes = AddEpsilonStatesForXXSubPaths(automaton);
// Look for paths (RRR/SS)
foreach (var startState in automaton.States)
{
// Now look for S * X^alpha * S states
var SSreachabilityDictionary = automaton.GetStatesReachableFromStateWithSymbol(startState, Constants.RegularLanguage.S,
useEpsilonStatesFromInitial: false, useEpsilonStatesAtEnd: true)
.ToDictionary((s) => s, (s) => ReachabilityStatus.Even())
.ApplyXTransitionToReachabilityDictionary(automaton)
.ApplySOrRTransitionToReachabilityDictionary(automaton, Constants.RegularLanguage.S, false);
foreach (var(finalState, reachability) in SSreachabilityDictionary)
{
if (AddTransitionsFromReachabilityStatus(automaton, startState, finalState, reachability))
{
changes = true;
}
}
// Add R * X^alpha1 * R * X^alpha2 * R
var RRRreachabilityDictionary = automaton.GetStatesReachableFromStateWithSymbol(startState, Constants.RegularLanguage.R,
useEpsilonStatesFromInitial: false, useEpsilonStatesAtEnd: true)
.ToDictionary((s) => s, (s) => ReachabilityStatus.Even())
.ApplyXTransitionToReachabilityDictionary(automaton)
.ApplySOrRTransitionToReachabilityDictionary(automaton, Constants.RegularLanguage.R, true)
.ApplyXTransitionToReachabilityDictionary(automaton)
.ApplySOrRTransitionToReachabilityDictionary(automaton, Constants.RegularLanguage.R, false);
foreach (var(finalState, reachability) in RRRreachabilityDictionary)
{
if (AddTransitionsFromReachabilityStatus(automaton, startState, finalState, reachability))
{
changes = true;
}
}
}
}
return(automaton);
}
private Dictionary <int, ReachabilityStatus> ApplyTransitionToReachabilityDictionary(Dictionary <int, ReachabilityStatus> reachabilityDictionary,
char symbol, bool includeEpsilon)
{
var newReachabilityDictionary = new Dictionary <int, ReachabilityStatus>();
foreach (var reachbilityLookup in reachabilityDictionary)
{
IEnumerable <KeyValuePair <int, ReachabilityStatus> > reachableStates = null !;
if (includeEpsilon)
{
reachableStates = _outgoingTransitionLookup[reachbilityLookup.Key].GetTransitionDictionary(symbol);
}
else
{
reachableStates = _automaton.TransitionMatrix.GetStates(reachbilityLookup.Key, symbol).Select(s =>
KeyValuePair.Create(s, ReachabilityStatus.Even()));
}
foreach (var state in reachableStates)
{
var newReachability = state.Value.Times(reachbilityLookup.Value);
if (!newReachabilityDictionary.TryGetValue(state.Key, out var newStatereachabilityStatus))
{
newStatereachabilityStatus = new ReachabilityStatus();
newReachabilityDictionary[state.Key] = newStatereachabilityStatus;
}
newStatereachabilityStatus.EvenReachable |= newReachability.EvenReachable;
newStatereachabilityStatus.OddReachable |= newReachability.OddReachable;
}
}
return(newReachabilityDictionary);
}