public bool IsAnswer(Clause aClause)
{
bool isAns = false;
if (answerClause.IsEmpty())
{
if (aClause.IsEmpty())
{
proofs.Add(new ProofFinal(aClause.GetProofStep(), new Dictionary<Variable, ITerm>()));
complete = true;
isAns = true;
}
} else
{
if (aClause.IsEmpty())
{
// This should not happen
// as added an answer literal to sos, which
// implies the database (i.e. premises) are
// unsatisfiable to begin with.
throw new InvalidOperationException(
"Generated an empty clause while looking for an answer, implies original KB or usable is unsatisfiable");
}
if (aClause.IsUnitClause()
&& aClause.IsDefiniteClause()
&& aClause.GetPositiveLiterals()[0].AtomicSentence.GetSymbolicName().Equals(
this.answerLiteral.AtomicSentence.GetSymbolicName())
)
{
IDictionary<Variable, ITerm> answerBindings = new Dictionary<Variable, ITerm>();
IList<ITerm> answerTerms =
aClause.GetPositiveLiterals()[0].AtomicSentence.GetArgs().Cast<ITerm>().ToList();
var idx = 0;
foreach (Variable v in this.answerLiteralVariables)
{
answerBindings[v] = answerTerms[idx];
idx++;
}
bool addNewAnswer = this.proofs.All(p => !p.GetAnswerBindings().Equals(answerBindings));
if (addNewAnswer)
{
this.proofs.Add(new ProofFinal(aClause.GetProofStep(), answerBindings));
}
isAns = true;
}
}
var ts = DateTime.Now - DateTime.MinValue;
if (ts.TotalMilliseconds > finishTime)
{
this.complete = true;
// Indicate that I have run out of query time
this.timedOut = true;
}
return isAns;
}
public override string GetProof()
{
var sb = new StringBuilder();
IList <Literal> nLits = implication.GetNegativeLiterals();
for (int i = 0; i < implication.GetNumberNegativeLiterals(); i++)
{
sb.Append(nLits[i].AtomicSentence);
if (i != (implication.GetNumberNegativeLiterals() - 1))
{
sb.Append(" AND ");
}
}
sb.Append(" => ");
sb.Append(implication.GetPositiveLiterals()[0]);
return(sb.ToString());
}
