public static string GetSimplified(IEnumerable <LogicItem> List, int variables, bool hazardsafe = false, bool lsba = false, bool negate = false)
{
var implicants = new List <Implicant>();
var items = (from i in List where i.Checked == true || i.Checked == null orderby i.Index ascending select i.Index).ToArray();
var careminterms = (from i in List where i.Checked == true orderby i.Index ascending select i.Index).ToArray();
foreach (var item in items)
{
var m = new Implicant();
m.Mask = LogicItem.GetBinaryValue(item, variables);
m.Minterms.Add(item);
implicants.Add(m);
}
//int count = 0;
while (Simplify(ref implicants))
{
//Populate a matrix.
bool[,] matrix = new bool[implicants.Count, items.Length]; //x, y
PopulateMatrix(ref matrix, implicants, items);
}
List <Implicant> selected;
if (hazardsafe)
{
selected = implicants;
}
else
{
selected = SelectImplicants(implicants, careminterms);
}
return(GetFinalExpression(selected, lsba, negate));
}
/// <summary>
/// Simplifies a givenset of implicants.
/// </summary>
private static bool Simplify(ref List <Implicant> implicants)
{
//Group by number of 1's and determine relationships by comparing.
var groups = (from i in Group(implicants) orderby i.Key select i).ToDictionary(i => i.Key, i => i.Value);
var relationships = new List <ImplicantRelationship>();
for (int i = 0; i < groups.Keys.Count; i++)
{
if (i == (groups.Keys.Count - 1))
{
break;
}
var thisGroup = groups[groups.Keys.ElementAt(i)];
var nextGroup = groups[groups.Keys.ElementAt(i + 1)];
var q = from a in thisGroup
from b in nextGroup
where Utility.GetDifferences(a.Mask, b.Mask) == 1
select new ImplicantRelationship(a, b);
relationships.AddRange(q);
}
//For each relationship, find the affected minterms and remove them.
//Then add a new implicant which simplifies the affected minterms.
foreach (ImplicantRelationship relationship in relationships)
{
var removeList = new List <Implicant>();
foreach (Implicant m in implicants)
{
if (relationship.A.Equals(m) || relationship.B.Equals(m))
{
removeList.Add(m);
}
}
foreach (Implicant m in removeList)
{
implicants.Remove(m);
}
var newImplicant = new Implicant
{
Mask = Utility.GetMask(relationship.A.Mask, relationship.B.Mask)
};
newImplicant.Minterms.AddRange(relationship.A.Minterms);
newImplicant.Minterms.AddRange(relationship.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));
}
