public Tableau(double[] min, double[][] constraintsLE)
{
Rows = new TableauRow[constraintsLE.Length];
int vars = min.Length;
mColNames = new string[vars + constraintsLE.Length + 1];
for (int i = 0; i < vars; i++)
{
mColNames[i] = "x" + (i + 1);
}
for (int i = 0; i < constraintsLE.Length; i++)
{
mColNames[vars + i] = "s" + (i + 1);
}
mColNames[vars + constraintsLE.Length] = "p";
for (int i = 0; i < constraintsLE.Length; i++)
{
if (constraintsLE[i].Length != vars + 1)
{
throw new Exception();
}
List <double> values = new List <double>(constraintsLE[i]);
values.RemoveAt(vars);
for (int j = 0; j < i; j++)
{
values.Add(0);
}
values.Add(1);
for (int j = i; j < constraintsLE.Length; j++)
{
values.Add(0);
}
Rows[i] = new TableauRow(vars + i, values.ToArray(), constraintsLE[i][vars]);
}
List <double> eqValues = new List <double>(min);
for (int i = 0; i < constraintsLE.Length; i++)
{
eqValues.Add(0);
}
eqValues.Add(1);
ResultRow = new TableauRow(vars + constraintsLE.Length, eqValues.ToArray(), 0);
}
static void SolveWithSimplex(Tableau tableau, double e)
{
while (tableau.ResultRow.Values.Any(v => v < 0))
{
tableau.Print(Console.WriteLine);
Console.WriteLine();
Console.WriteLine();
Console.WriteLine();
int pivotColumn = tableau.ResultRow.Values.Select((v, i) => new { idx = i, value = v })
.OrderBy(vi => vi.value).FirstOrDefault(vi => vi.value < 0)?.idx ?? -1;
if (pivotColumn == -1)
{
break;
}
int pivotRowIdx = tableau.Rows.Select((row, i) => new { row, i })
.Where(ri => ri.row.Values[pivotColumn] > 0)
.MinBy(ri => ri.row.Answer / ri.row.Values[pivotColumn])
.FirstOrDefault()?.i ?? -1;
if (pivotRowIdx == -1)
{
break;
}
tableau.Rows[pivotRowIdx].PivotIndex = pivotColumn;
TableauRow pivotRow = tableau.Rows[pivotRowIdx];
for (int i = 0; i < tableau.Rows.Length; i++)
{
if (i != pivotRowIdx)
{
ClearCell(ref tableau.Rows[i], pivotRow, pivotColumn, e);
}
}
ClearCell(ref tableau.ResultRow, pivotRow, pivotColumn, e);
}
tableau.Print(Console.WriteLine);
}
private static void ClearCell(ref TableauRow thisRow, TableauRow pivotRow, int pivotColumn, double e)
{
if (Math.Abs(thisRow.Values[pivotColumn]) > e)
{
double thisValue = thisRow.Values[pivotColumn];
double pivotValue = pivotRow.Values[pivotColumn];
if (Math.Sign(thisValue) == Math.Sign(pivotValue))
{
pivotValue = -Math.Abs(pivotValue);
}
else
{
pivotValue = Math.Abs(pivotValue);
}
thisValue = Math.Abs(thisValue);
for (int j = 0; j < pivotRow.Values.Length; j++)
{
thisRow.Values[j] = pivotValue * thisRow.Values[j] + thisValue * pivotRow.Values[j];
}
thisRow.Answer = pivotValue * thisRow.Answer + thisValue * pivotRow.Answer;
}
}
