public STb <FUNC, TERM, SORT> Minimize()
{
var s = stb.Solver;
var alphaSort = s.MkOptionSort(stb.InputSort);
var autoSort = s.MkTupleSort(alphaSort, stb.OutputListSort, stb.RegisterSort, stb.RegisterSort);
var autoVar = s.MkVar(3, autoSort);
var autoInput = s.MkProj(0, autoVar);
var autoSomeInput = s.MkGetSomeValue(autoInput);
var autoOutputList = s.MkProj(1, autoVar);
var autoOldReg = s.MkProj(2, autoVar);
var autoNewReg = s.MkProj(3, autoVar);
Func <TERM, TERM> finalSubstitute = (t) => s.ApplySubstitution(t, stb.RegVar, autoOldReg);
Func <TERM, TERM> nonFinalSubstitute = (t) => finalSubstitute(s.ApplySubstitution(t, stb.InputVar, autoSomeInput));
int acceptingState = stb.States.Max() + 1;
int errorState = stb.States.Max() + 2;
var moves = new List <Move <TERM> >();
foreach (var state in stb.States)
{
var nonFinalConds = new List <TERM>();
foreach (var nonFinal in st.GetNonFinalMovesFrom(state))
{
var rule = nonFinal.Label;
var conds = new List <TERM>();
conds.Add(s.MkIsSome(autoInput));
conds.Add(nonFinalSubstitute(rule.Guard));
var outputList = autoOutputList;
foreach (var yield in rule.Output)
{
conds.Add(s.MkIsCons(outputList));
conds.Add(s.MkEq(s.MkFirstOfList(outputList), nonFinalSubstitute(yield)));
outputList = s.MkRestOfList(outputList);
}
conds.Add(s.MkIsNil(outputList));
conds.Add(s.MkEq(autoNewReg, nonFinalSubstitute(rule.Update)));
var cond = s.MkAnd(conds);
moves.Add(Move <TERM> .Create(state, nonFinal.TargetState, cond));
nonFinalConds.Add(cond);
}
var finalConds = new List <TERM>();
foreach (var rule in st.GetFinalRules(state))
{
var conds = new List <TERM>();
conds.Add(s.MkIsNone(autoInput));
conds.Add(finalSubstitute(rule.Guard));
var outputList = autoOutputList;
foreach (var yield in rule.Output)
{
conds.Add(s.MkIsCons(outputList));
conds.Add(s.MkEq(s.MkFirstOfList(outputList), finalSubstitute(yield)));
outputList = s.MkRestOfList(outputList);
}
conds.Add(s.MkIsNil(outputList));
var cond = s.MkAnd(conds);
moves.Add(Move <TERM> .Create(state, acceptingState, cond));
finalConds.Add(cond);
}
}
//moves.Add(Move<TERM>.Create(errorState, errorState, s.True));
var auto = Automaton <TERM> .Create(stb.Solver, stb.InitialState, new int[] { acceptingState }, moves);
auto.CheckDeterminism(stb.Solver);
var blocks = auto.BookkeepingMinimize(stb.Solver);
Func <STbRule <TERM>, STbRule <TERM> > redirect = null;
redirect = r =>
{
switch (r.RuleKind)
{
case STbRuleKind.Undef:
return(r);
case STbRuleKind.Base:
return(new BaseRule <TERM>(r.Yields, r.Register, blocks[r.State].GetRepresentative()));
case STbRuleKind.Ite:
var t = redirect(r.TrueCase);
var f = redirect(r.FalseCase);
return(new IteRule <TERM>(r.Condition, t, f));
default:
throw new NotImplementedException();
}
};
var minimized = new STb <FUNC, TERM, SORT>(stb.Solver, stb.Name + "_min", stb.InputSort, stb.OutputSort, stb.RegisterSort, stb.InitialRegister,
blocks[stb.InitialState].GetRepresentative());
var representatives = new HashSet <int>();
foreach (var state in stb.States)
{
representatives.Add(blocks[state].GetRepresentative());
}
foreach (var state in representatives)
{
minimized.AssignRule(state, redirect(stb.GetRuleFrom(state)).CollapseRedundantITEs(s));
minimized.AssignFinalRule(state, redirect(stb.GetFinalRuleFrom(state)).CollapseRedundantITEs(s));
}
return(minimized);
}
