public void Join(Conjunct c)
{
foreach (var d in c._disjuncts)
{
Join(d);
}
}
public Conjunct Add(Conjunct c)
{
var ans = new Conjunct(this);
ans.Join(c);
return(ans);
}
public Conjunct Add(Disjunct d)
{
var ans = new Conjunct(this);
ans.Join(d);
return(ans);
}
public Conjunct(Conjunct c) : base()
{
_disjuncts = new List <Disjunct>();
foreach (var d in c._disjuncts)
{
_disjuncts.Add(new Disjunct(d));
}
}
public Conjunct Negation()
{
var ans = new Conjunct();
foreach (var d in _disjuncts)
{
var c = d.Negation();
ans = ans.Disjunction(c);
}
return(ans);
}
public Conjunct Disjunction(Conjunct c)
{
var ans = new Conjunct();
if (IsEmpty())
{
return(new Conjunct(c));
}
if (c.IsEmpty())
{
return(new Conjunct(this));
}
foreach (var d1 in _disjuncts)
{
foreach (var d2 in c._disjuncts)
{
var d = d1.Add(d2);
ans.Join(d);
}
}
return(ans);
}
public bool IsNonContradictory(ref Estimation contrary, HashSet <Literal> used)
{
int firstContraryDisjunctIdx = 0, secondContraryDisjunctIdx = 0;
var conjunctCopy = new Conjunct(this);
return(ProcessResolutionsMethod(ref contrary));
bool ProcessResolutionsMethod(ref Estimation contraryInstance)
{
while (true)
{
conjunctCopy._disjuncts =
conjunctCopy._disjuncts.Distinct(new Disjunct.DisjunctComparer()).ToList();
if (SearchForContraryPair(ref firstContraryDisjunctIdx, ref secondContraryDisjunctIdx))
{
Debug.WriteLine("\nNow conjunct looks like "); conjunctCopy.Print();
var d1 = conjunctCopy._disjuncts[firstContraryDisjunctIdx];
var d2 = conjunctCopy._disjuncts[secondContraryDisjunctIdx];
Debug.WriteLine("\nHas contrary pair: "); d1.Print();
Debug.WriteLine(" and "); d2.Print();
var resolventa = Disjunct.GetResolventa(d1, d2);
Debug.WriteLine("\nTheir resolventa: "); resolventa.Print();
if (d1.IsElementary() && d2.IsElementary())
{
conjunctCopy._disjuncts.Remove(d1);
conjunctCopy._disjuncts.Remove(d2);
}
else
{
if (!d1.IsElementary())
{
conjunctCopy._disjuncts.Remove(d1); // At(firstContraryDisjunctIdx);
}
if (!d2.IsElementary())
{
conjunctCopy._disjuncts.Remove(d2); // At(secondContraryDisjunctIdx);
}
}
if (!resolventa.IsEmpty())
{
conjunctCopy._disjuncts.Add(resolventa);
}
}
else
{
if (conjunctCopy._disjuncts.Count == 0)
{
return(true);
}
break;
}
}
var startSingle =
conjunctCopy._disjuncts.FindAll(d => d.IsElementary());
contraryInstance = new Estimation();
foreach (var d in startSingle)
{
var l = d.Literal(0);
contraryInstance.EstimateVariable(l, Estimation.True);
}
conjunctCopy = new Conjunct(this);
while (true)
{
conjunctCopy._disjuncts =
conjunctCopy._disjuncts.Distinct(new Disjunct.DisjunctComparer()).ToList();
foreach (var d in conjunctCopy._disjuncts)
{
if (d.IsElementary())
{
if (contraryInstance.GetEstimation(d.Literal(0)) == Estimation.False)
{
return(true);
}
else
{
contraryInstance.EstimateVariable(d.Literal(0), Estimation.True);
}
}
else if (d.Size == 2)
{
var l1 = d.Literal(0);
var l2 = d.Literal(1);
int est1 = contraryInstance.GetEstimation(l1);
int est2 = contraryInstance.GetEstimation(l2);
if (est1 == Estimation.True || est2 == Estimation.True)
{
continue;
}
if (est1 == Estimation.False && est2 == Estimation.False)
{
return(true);
}
if (est1 == Estimation.Undefined)
{
contraryInstance.EstimateVariable(l1, Estimation.True);
}
else if (est2 == Estimation.Undefined)
{
contraryInstance.EstimateVariable(l2, Estimation.True);
}
}
}
if (SearchForContraryPair(ref firstContraryDisjunctIdx, ref secondContraryDisjunctIdx))
{
Debug.WriteLine("\nNow conjunct looks like "); conjunctCopy.Print();
var d1 = conjunctCopy._disjuncts[firstContraryDisjunctIdx];
var d2 = conjunctCopy._disjuncts[secondContraryDisjunctIdx];
Debug.WriteLine("\nHas contrary pair: "); d1.Print();
Debug.WriteLine(" and "); d2.Print();
var resolventa = Disjunct.GetResolventa(d1, d2);
Debug.WriteLine("\nTheir resolventa: "); resolventa.Print();
if (d1.IsElementary() && d2.IsElementary())
{
conjunctCopy._disjuncts.Remove(d1);
conjunctCopy._disjuncts.Remove(d2);
}
else
{
if (!d1.IsElementary())
{
conjunctCopy._disjuncts.Remove(d1); // At(firstContraryDisjunctIdx);
}
if (!d2.IsElementary())
{
conjunctCopy._disjuncts.Remove(d2); // At(secondContraryDisjunctIdx);
}
}
if (!resolventa.IsEmpty())
{
conjunctCopy._disjuncts.Add(resolventa);
}
}
else
{
if (conjunctCopy._disjuncts.Count == 0)
{
return(true);
}
break;
}
}
foreach (var usedVar in used)
{
if (contraryInstance.GetEstimation(usedVar) == Estimation.Undefined)
{
contraryInstance.EstimateVariable(usedVar, Estimation.True);
}
}
return(false);
}
bool SearchForContraryPair(ref int i1, ref int i2)
{
for (int i = 0; i < conjunctCopy._disjuncts.Count; i++)
{
for (int j = i + 1; j < conjunctCopy._disjuncts.Count; j++)
{
var d1 = conjunctCopy._disjuncts[i];
var d2 = conjunctCopy._disjuncts[j];
if (i != j && d1.HasContraryPair(d2))
{
i1 = i;
i2 = j;
return(true);
}
}
}
return(false);
}
}