static void Main(string[] args)
{
//double[,] matrix = {{ 1, -2, 1, 2 },
// { 2, -5, -1, -1 },
// { -7, 0, 1, -2 }};
double[,] matrix = { { 5, -5, -3, 4, -11 },
{ 1, -4, -6, -4, -10 },
{ -2, -5, 4, -5, -12 },
{ -3, -3, 5, -5, 8 } };
double[,] initial = matrix.Clone() as double[, ];
matrix.Print();
Console.WriteLine("Forward walkthrough");
for (int i = 0; i < matrix.RowCount() - 1; i++)
{
Console.WriteLine("Iteration {0}", i + 1);
matrix
.SwapRows(i, matrix
.Column(i)
.StartingAt(i)
.Abs()
.MaxElementIndex() + i)
.Print();
for (int j = i + 1; j < matrix.RowCount(); j++)
{
Console.WriteLine("Sub iteration {0}", j - i);
matrix
.AddToRow(j, matrix
.Row(i)
.MultBy(-matrix[j, i] / matrix[i, i]))
.Print();
}
}
Console.WriteLine("Backward walkthrough");
double[] solution = new double[matrix.RowCount()];
for (int i = matrix.RowCount() - 1; i >= 0; i--)
{
solution[i] = (matrix[i, matrix.ColumnCount() - 1] -
matrix
.Row(i)
.Coefficients()
.MultWith(solution)
.SumElements()) /
matrix[i, i];
solution.Print();
}
Console.WriteLine("Check");
for (int i = 0; i < initial.RowCount(); i++)
{
Console.WriteLine("Equation {0}:", i + 1);
initial.Row(i).Print();
double delta = initial[i, initial.ColumnCount() - 1] -
initial
.Row(i)
.Coefficients()
.MultWith(solution)
.SumElements();
Console.WriteLine("Delta: {0}", delta);
}
}
