public override Formula Simplify()
{
Formula fSimplified = null;
if (Simplified)
return this;
if( Operator == "not" )
fSimplified = Negate();
if (Operands.Count == 1)
fSimplified = Operands[0].Simplify();
if (Operator == "when")
{
CompoundFormula cfNew = new CompoundFormula(Operator);
Formula fFirst = Operands[0].Simplify();
Formula fSecond = Operands[1].Simplify();
cfNew.SimpleAddOperand(fFirst);
if (IsSimpleAnd(fFirst) && IsSimpleAnd(fSecond))
{
HashSet<Predicate> lFirst = fFirst.GetAllPredicates();
HashSet<Predicate> lSecond = fSecond.GetAllPredicates();
CompoundFormula cfSecond = new CompoundFormula("and");
foreach (Predicate p in lSecond)
if (!lFirst.Contains(p))
cfSecond.AddOperand(p);
cfNew.SimpleAddOperand(cfSecond);
}
else
{
cfNew.SimpleAddOperand(fSecond);
}
cfNew.Simplified = true;
fSimplified = cfNew;
}
else if (Operator == "and" || Operator == "or" || Operator == "oneof")
{
/*
if (Operands.Count == 0)
{
if (Operator == "and")
return new PredicateFormula(new GroundedPredicate(Domain.TRUE_PREDICATE));
if (Operator == "or" || Operator == "oneof")
return new PredicateFormula(new GroundedPredicate(Domain.FALSE_PREDICATE));
}
* */
CompoundFormula cfNew = new CompoundFormula(Operator);
foreach (Formula f in Operands)
{
Formula fSimplify = f.Simplify();
if (fSimplify is CompoundFormula)
{
CompoundFormula cf = (CompoundFormula)fSimplify;
if (cf.Operator == Operator)
{
foreach (Formula ff in cf.Operands)
cfNew.AddOperand(ff);
}
else
cfNew.AddOperand(cf);
}
else if (fSimplify is ProbabilisticFormula)
{
cfNew.AddOperand(fSimplify);
}
else
{
Predicate p = ((PredicateFormula)fSimplify).Predicate;
if (p.Name == Domain.TRUE_PREDICATE)
{
if (Operator == "or")
return fSimplify;
}
else if (p.Name == Domain.FALSE_PREDICATE)
{
if (Operator == "and")
return fSimplify;
}
else
cfNew.AddOperand(fSimplify);
}
}
if (cfNew.Operands.Count == 1)
return cfNew.Operands[0];
if (cfNew.Operator == "or")
cfNew = cfNew.RemoveRedundancies();
fSimplified = cfNew;
}
if( fSimplified is CompoundFormula )
((CompoundFormula)fSimplified).Simplified = true;
return fSimplified;
}
