/*
* Groups binary numbers based on 1's.
* Stores group in a hashtable associated with a list (bucket) for each group.
*/
private static ImplicantGroup Group(ImplicantCollection implicants)
{
ImplicantGroup group = new ImplicantGroup();
foreach (Implicant m in implicants)
{
int count = GetOneCount(m.Mask);
if (!group.ContainsKey(count))
{
group.Add(count, new ImplicantCollection());
}
group[count].Add(m);
}
return(group);
}
/*
* Simplifies a givenset of implicants.
*/
private static bool Simplify(ref ImplicantCollection implicants)
{
/*
* Group by number of 1's and determine relationships by comparing.
*/
ImplicantGroup group = Group(implicants);
ImplicantRelationshipCollection relationships = new ImplicantRelationshipCollection();
for (int i = 0; i < group.Keys.Count; i++)
{
if (i == (group.Keys.Count - 1))
{
break;
}
ImplicantCollection thisGroup = group[group.Keys.ElementAt(i)];
ImplicantCollection nextGroup = group[group.Keys.ElementAt(i + 1)];
foreach (Implicant a in thisGroup)
{
foreach (Implicant b in nextGroup)
{
if (GetDifferences(a.Mask, b.Mask) == 1)
{
relationships.Add(new ImplicantRelationship(a, b));
}
}
}
}
/*
* For each relationship, find the affected minterms and remove them.
* Then add a new implicant which simplifies the affected minterms.
*/
foreach (ImplicantRelationship r in relationships)
{
ImplicantCollection rmList = new ImplicantCollection();
foreach (Implicant m in implicants)
{
if (r.a.Equals(m) || r.b.Equals(m))
{
rmList.Add(m);
}
}
foreach (Implicant m in rmList)
{
implicants.Remove(m);
}
Implicant newImplicant = new Implicant();
newImplicant.Mask = GetMask(r.a.Mask, r.b.Mask);
newImplicant.Minterms.AddRange(r.a.Minterms);
newImplicant.Minterms.AddRange(r.b.Minterms);
bool exist = false;
foreach (Implicant m in implicants)
{
if (m.Mask == newImplicant.Mask)
{
exist = true;
}
}
if (!exist) //Why am I getting dupes?
{
implicants.Add(newImplicant);
}
}
//Return true if simplification occurred, false otherwise.
return(!(relationships.Count == 0));
}
