public static double[] Ask(Query q, BayesNet net)
{
Dictionary <string, bool?> evidenceVariables = q.EvidenceVariables;
double[] probDist = new double[2];
// true probability
evidenceVariables[q.QueryVariable] = true;
probDist[0] = EnumerateAll(net, net.GetVariables(), evidenceVariables);
// false probability
evidenceVariables[q.QueryVariable] = false;
probDist[1] = EnumerateAll(net, net.GetVariables(), evidenceVariables);
// System.out.println( probDist[0] + " " + probDist[1]);
// return probDist;
double[] normalized = Util.Util.Normalize(probDist);
// System.out.println( normalized[0] + " " + normalized[1]);
return(normalized);
}
private static double EnumerateAll(BayesNet net, IList <string> unprocessedVariables,
Dictionary <string, bool?> evidenceVariables)
{
if (unprocessedVariables.Count == 0)
{
return(1.0);
}
var y = unprocessedVariables[0];
if (evidenceVariables.Keys.Contains(y))
{
double probYGivenParents = net.ProbabilityOf(y, evidenceVariables[y], evidenceVariables);
double secondTerm = EnumerateAll(net, Util.Util.Rest(unprocessedVariables), evidenceVariables);
return(probYGivenParents * secondTerm);
}
else
{
double sigma = 0.0;
Dictionary <string, bool?> clone1 = CloneEvidenceVariables(evidenceVariables);
clone1[y] = true;
double probYTrueGivenParents = net.ProbabilityOf(y,
true, clone1);
double secondTerm = EnumerateAll(net, Util.Util.Rest(unprocessedVariables), clone1);
double trueProbabilityY = probYTrueGivenParents * secondTerm;
Dictionary <string, bool?> clone2 = CloneEvidenceVariables(evidenceVariables);
clone2[y] = false;
double probYFalseGivenParents = net.ProbabilityOf(y,
false, clone2);
secondTerm = EnumerateAll(net, Util.Util.Rest(unprocessedVariables),
clone2);
double falseProbabilityY = probYFalseGivenParents * secondTerm;
// System.out.print(secondTerm + " ) )");
sigma = trueProbabilityY + falseProbabilityY;
return(sigma);
}
}
