public override bool Equals(object obj)
{
TruthTable table = (TruthTable)obj;
if (table == this)
{
return(true);
}
else if (table == null)
{
return(false);
}
else if (this.outputValues.Count != table.outputValues.Count)
{
return(false);
}
else
{
for (int i = 0; i < this.outputValues.Count; i++)
{
if (this.outputValues[i] != table.outputValues[i])
{
return(false);
}
}
return(true);
}
}
/*
* This uses patricks method or a rough version of it. It is assumed to be demonstoubly slow, and improvement is sure to exist
*/
private List <Implicant> patricksMethod(Tuple <List <Implicant>, List <int> > maybeEssential)
{
String patricksStringExpression = "";
//Loops over each minterm
for (int i = 0; i < maybeEssential.Item2.Count; i++)
{
// A Sum of Product String
String SOP = "(";
//Loops over each Implicant
for (int j = 0; j < maybeEssential.Item1.Count; j++)
{
//Checks if the specified implicant contains a reference to the targer minterm
if (maybeEssential.Item1[j].parents.Contains(maybeEssential.Item2[i]))
{
//Simply the First implicnt is labeled A, Second B and so on
if (SOP.Length != 1)
{
SOP += "+";
}
SOP += (char)(j + 'A');
}
}
patricksStringExpression += SOP + ")";
if (i != maybeEssential.Item2.Count - 1)
{
patricksStringExpression += "*";
}
}
//Just a quick check to see if the expression doesnt exist. This is the case where there exists no possibly essential implicants
if (patricksStringExpression.Equals(""))
{
return(new List <Implicant>());
}
//Creates a new BooleanExpression to represent the expression
BooleanExpression patricksExpression = new BooleanExpression(patricksStringExpression);
TruthTable patricksTable = new TruthTable(patricksExpression);
//Console.WriteLine(patricksTable.ToString());
List <List <Int32> > InputWithLowestImplicantCount = new List <List <int> >();
for (int i = 0; i < patricksTable.inputValues.Count; i++)
{
//Only enter if the table output is true for this input combo (input i coresponds directly to output i)
if (patricksTable.outputValues[i] == 1)
{
//if master list is empty add first elemtn into it, garunteed to have less ones than null
if (!InputWithLowestImplicantCount.Any())
{
InputWithLowestImplicantCount.Add(patricksTable.inputValues[i]);
}
//if list has elements
else
{
//Checks idfthe current input has a lower number of ones, and thus implicants than the current lowest
if (this.numOnes(patricksTable.inputValues[i]) < this.numOnes(InputWithLowestImplicantCount[0]))
{
//Clear and add new lowest to list
InputWithLowestImplicantCount.Clear();
InputWithLowestImplicantCount.Add(patricksTable.inputValues[i]);
}
}
}
}
//At this point you have a list with the input combinations with the fewest number of implicants
// Now you need to convert all of those List of ints into Implicant representations again
List <List <Implicant> > bestCombinations = new List <List <Implicant> >();
for (int i = 0; i < InputWithLowestImplicantCount.Count; i++)
{
bestCombinations.Add(new List <Implicant>());
//Each list is in the format 001 or 100 coresponding to some number of variables, in this example 3. The Most Significant bit is A, then B
//And so on. A represents the first Implicant in the maybe essential Item 1 of The input tuple. So find that minterm by below
for (int j = 0; j < InputWithLowestImplicantCount[i].Count; j++)
{
if (InputWithLowestImplicantCount[i][j] == 1)
{
bestCombinations[i].Add(maybeEssential.Item1[j]);
}
}
}
//If there is more than one best combination than the Truly best one will be the one with the lowest number of total variables
int LowestNumVariables = 0;
int LowestNumVariablesIndex = 0;
//Case where youve found the best combo, so return it
if (bestCombinations.Count == 1)
{
return(bestCombinations[0]);
}
else
{
if (bestCombinations.Count != 1)
{
for (int i = 0; i < bestCombinations.Count; i++)
{
int varCount = 0;
for (int j = 0; j < bestCombinations[i].Count; j++)
{
varCount += bestCombinations[i][j].numVariables();
}
if (varCount < LowestNumVariables)
{
LowestNumVariablesIndex = i;
}
}
}
return(bestCombinations[LowestNumVariablesIndex]);
}
}
//generates the truth table for this expression object
private void GenerateTruthTable()
{
this.truthTable = new TruthTable(this);
}
