internal CPT PointWiseProduct(CPT other)
{
IEnumerable <RandomVariable> commonVars = this.vars.Intersect(other.vars);
HashSet <RandomVariable> rightVars = new HashSet <RandomVariable>(other.vars);
rightVars.ExceptWith(commonVars);
int[] commVarsIndicesInLeft = commonVars.Select <RandomVariable, int>(v => keyPosMap[v]).ToArray();
int[] commVarsIndicesInRight = commonVars.Select <RandomVariable, int>(v => other.keyPosMap[v]).ToArray();
List <RandomVariable> varsInResultCPT = new List <RandomVariable>(this.vars);
List <RandomVariable> rightVarsInResult = new List <RandomVariable>(other.vars);
rightVarsInResult.RemoveAll(v => commonVars.Contains(v));
varsInResultCPT.AddRange(rightVarsInResult);
Dictionary <RandomVariable, int> newKeyPosMap = new Dictionary <RandomVariable, int>();
for (int i = 0; i < varsInResultCPT.Count(); i++)
{
newKeyPosMap.Add(varsInResultCPT[i], i);
}
int newCptSize = varsInResultCPT.Aggregate <RandomVariable, int>(1, (acc, v) => acc * v.tokens.Length);
CptEntry[] newCptEntries = new CptEntry[newCptSize];
Dictionary <CptKey, List <CptEntry> > mapping = new Dictionary <CptKey, List <CptEntry> >();
CategoriseEntries(other, commVarsIndicesInRight, mapping);
int cptIndex = 0;
foreach (CptEntry leftEntry in this.cpt)
{
CptKey key = leftEntry.key.Extract(commVarsIndicesInLeft);
List <CptEntry> right = mapping[key];
foreach (CptEntry rightEntry in right)
{
CptKey newKey = leftEntry.key.Concat(rightEntry.key.Remove(commVarsIndicesInRight));
newCptEntries[cptIndex] = new CptEntry(newKey, leftEntry.value * rightEntry.value);
cptIndex++;
}
}
return(new CPT(varsInResultCPT.ToArray(), newKeyPosMap, newCptEntries));
}
internal CPT(RandomVariable[] vars, double[] values)
{
this.vars = vars;
this.keyPosMap = new Dictionary <RandomVariable, int>();
this.cpt = new CptEntry[values.Length];
for (int i = 0; i < vars.Length; i++)
{
keyPosMap.Add(vars[i], i);
}
CptKey[] keys = Enumerable.Range(1, values.Length).Select(_ => new CptKey(vars.Length)).ToArray();
SetKeys(new ArraySegment <CptKey>(keys), new ArraySegment <RandomVariable>(vars));
for (int i = 0; i < cpt.Length; i++)
{
cpt[i] = new CptEntry(keys[i], values[i]);
}
}