public CNF Transform()
{
var res = Transform(logTree.ReturnRoot());
cnf = res.Item2;
cnf.Add(res.Item1);
return(cnf);
}
private Tuple <Literal, CNF> Transform(INode node)
{
if (node.GetType() == typeof(Tree.AndNode))
{
var myLit = new Literal(id);
vars.Add(id);
id--;
var res1 = Transform(node.GetRight());
var res2 = Transform(node.GetLeft());
var cnfUnion = new CNF();
cnfUnion.Add(res1.Item2);
cnfUnion.Add(res2.Item2);
// ∆0 = ∆2 ∪ {¬p ∨ `1, ¬p ∨ `2, ¬`1 ∨ ¬`2 ∨ p}
cnfUnion.Add(new Literal[] { myLit.Inversed(), res1.Item1 });
cnfUnion.Add(new Literal[] { myLit.Inversed(), res2.Item1 });
cnfUnion.Add(new Literal[] { myLit, res1.Item1.Inversed(), res2.Item1.Inversed() });
return(Tuple.Create(myLit, cnfUnion));
}
else if (node.GetType() == typeof(Tree.OrNode))
{
var myLit = new Literal(id);
vars.Add(id);
id--;
var res1 = Transform(node.GetRight());
var res2 = Transform(node.GetLeft());
var cnfUnion = new CNF();
cnfUnion.Add(res1.Item2);
cnfUnion.Add(res2.Item2);
// ∆0 = ∆2 ∪ {¬p ∨ `1 ∨ `2, ¬`1 ∨ p, ¬`2 ∨ p}
cnfUnion.Add(new Literal[] { myLit.Inversed(), res1.Item1, res2.Item1 });
cnfUnion.Add(new Literal[] { myLit, res2.Item1.Inversed() });
cnfUnion.Add(new Literal[] { myLit, res1.Item1.Inversed() });
return(Tuple.Create(myLit, cnfUnion));
}
else if (node.GetType() == typeof(Tree.NotNode))
{
if (node.GetLeft().GetType() == typeof(Tree.TermNode))
{
int num = ((Tree.TermNode)node.GetLeft()).Num;
vars.Add(num);
return(Tuple.Create(new Literal(num, true), new CNF())); //not x_i
}
else
{
var cnfLoc = Transform(node.GetLeft());
return(Tuple.Create(cnfLoc.Item1.Inversed(), cnfLoc.Item2));
}
}
else if (node.GetType() == typeof(Tree.TermNode))
{
int num = ((Tree.TermNode)node).Num;
vars.Add(num);
return(Tuple.Create(new Literal(num), new CNF())); // x_i
}
else
{
throw new ArgumentException();
}
}
private bool DPLLAlgo(CNF f, List <int> unchLit, Dictionary <int, int> totalModel)
{
//Console.WriteLine(f);
CNF newf = f;
do
{
if (newf.IsEmpty())
{
model = new Dictionary <int, int>(totalModel);
return(true);
}
if (newf.HasEmptyConj())
{
return(false);
}
var unionLit = newf.GetUnionDisj();
HashSet <Literal> newLit = new HashSet <Literal>();
foreach (var u in unionLit)
{
UnitPropagation(u, totalModel, newLit);
}
unchLit.RemoveAll(x => newLit.Select(y => y.Name).Contains(x));
newf = EliminatePureLiterals(newf, newLit);
} while (newf.GetUnionDisj().Count > 0);
if (newf.IsEmpty())
{
model = new Dictionary <int, int>(totalModel);
return(true);
}
if (newf.HasEmptyConj())
{
return(false);
}
var l = ChooseLiteral(unchLit);
if (l.Name == 0) // нет невыьранных литералов
{
Console.WriteLine("no Lit: " + newf.Count);
return(DPLLAlgo(newf, unchLit, totalModel));
}
else
{
newf.Add(l);
if (DPLLAlgo(newf, new List <int>(unchLit), new Dictionary <int, int>(totalModel)))
{
return(true);
}
else
{
//Console.WriteLine("Back Track: " + l + " " + newf.Count + " UncLit:" + unchLit.Count);
newf.AddInversed(l);
return(DPLLAlgo(newf, unchLit, totalModel));
}
}
}