public static Vector LU(Matrix A, Vector b)
{
double sum;
LU lu = new LU(A);
Matrix Rez = lu.L_U;
Vector B_i = lu.M * b;
Vector X = new Vector(A.ColumnCount);
for (int i = A.ColumnCount - 1; i >= 0; i--)
{
if (i == A.ColumnCount - 1)
{
X[i] = B_i[i] / Rez[i, i];
}
else
{
sum = 0;
for (int j = i; j < A.ColumnCount; j++)
{
sum += Rez[i, j] * X[j];
}
X[i] = (B_i[i] - sum) / Rez[i, i];
}
}
return X;
}
public static double Determinant(Matrix val)
{
LU lu = new LU(val);
double R = 1;
Matrix temp = new Matrix(lu.L_U);
for (int i = 0; i < temp.RowCount; i++)
{
R *= temp[i, i];
}
return Math.Round(R, 2) * Math.Pow(-1, lu.number_of_permutations);
}