/// <summary>
/// Initializes a new instance of the <see cref="EpsilonClosure"/> class.
/// </summary>
/// <param name="automaton">The automaton from to which <paramref name="state"/> belongs.</param>
/// <param name="state">The state, which epsilon closure this instance will represent.</param>
internal EpsilonClosure(
Automaton <TSequence, TElement, TElementDistribution, TSequenceManipulator, TThis> automaton,
State state)
{
this.weightedStates = new List <(State, Weight)>(DefaultStateListCapacity);
// Optimize for a very common case: a single-node closure
bool singleNodeClosure = true;
Weight selfLoopWeight = Weight.Zero;
foreach (var transition in state.Transitions)
{
if (transition.IsEpsilon)
{
if (transition.DestinationStateIndex != state.Index)
{
singleNodeClosure = false;
break;
}
selfLoopWeight += transition.Weight;
}
}
if (singleNodeClosure)
{
Weight stateWeight = Weight.ApproximateClosure(selfLoopWeight);
this.weightedStates.Add((state, stateWeight));
this.EndWeight = stateWeight * state.EndWeight;
}
else
{
Condensation condensation = automaton.ComputeCondensation(state, tr => tr.IsEpsilon, true);
for (int i = 0; i < condensation.ComponentCount; ++i)
{
StronglyConnectedComponent component = condensation.GetComponent(i);
for (int j = 0; j < component.Size; ++j)
{
State componentState = component.GetStateByIndex(j);
this.weightedStates.Add((componentState, condensation.GetWeightFromRoot(componentState)));
}
}
this.EndWeight = condensation.GetWeightToEnd(state.Index);
}
}
/// <summary>
/// Initializes a new instance of the <see cref="EpsilonClosure"/> class.
/// </summary>
/// <param name="state">The state, which epsilon closure this instance will represent.</param>
internal EpsilonClosure(State state)
{
Argument.CheckIfValid(!state.IsNull, nameof(state));
// Optimize for a very common case: a single-node closure
bool singleNodeClosure = true;
Weight selfLoopWeight = Weight.Zero;
for (int i = 0; i < state.TransitionCount; ++i)
{
Transition transition = state.GetTransition(i);
if (transition.IsEpsilon)
{
if (transition.DestinationStateIndex != state.Index)
{
singleNodeClosure = false;
break;
}
selfLoopWeight = Weight.Sum(selfLoopWeight, transition.Weight);
}
}
if (singleNodeClosure)
{
Weight stateWeight = Weight.ApproximateClosure(selfLoopWeight);
this.weightedStates.Add(Pair.Create(state, stateWeight));
this.EndWeight = Weight.Product(stateWeight, state.EndWeight);
}
else
{
Condensation condensation = state.Owner.ComputeCondensation(state, tr => tr.IsEpsilon, true);
for (int i = 0; i < condensation.ComponentCount; ++i)
{
StronglyConnectedComponent component = condensation.GetComponent(i);
for (int j = 0; j < component.Size; ++j)
{
State componentState = component.GetStateByIndex(j);
this.weightedStates.Add(Pair.Create(componentState, condensation.GetWeightFromRoot(componentState)));
}
}
this.EndWeight = condensation.GetWeightToEnd(state);
}
}
