/// <summary>
/// Calculation inverse of matrix
/// http://www.mathwords.com/i/inverse_of_a_matrix.htm using method 3
/// </summary>
/// Coded by : ahmed osama ([email protected])
/// <summary>
/// Parameters of entries:
/// </summary>
/// <param name="MAT">Array with numeration of elements[0..N-1, 0..N-1]</param>
/// <param name="N">Dimension of matrix A</param>
public double[,] InvMatrix(double[,] MAT, int N)
{
double[,] ResultMat = new double[N, N];
MatrixDeterminant MatDet = new MatrixDeterminant();
double DET = MatDet.MatrixDet(MAT, N);
if (DET == 0)
{
throw new System.ArgumentException("Matrix is singular ");
}
MatrixCofactor MatCof = new MatrixCofactor();
ResultMat = MatCof.AdjointMatrix(MAT, N);
for (int y = 0; y < N; y++)
{
for (int x = 0; x < N; x++)
{
ResultMat[x, y] = ResultMat[x, y] / DET;
}
}
return(ResultMat);
}
/// <summary>
/// Calculation cofactor of matrix
/// http://www.mathwords.com/c/cofactor_matrix.htm
/// </summary>
/// Coded by : ahmed osama ([email protected])
/// <summary>
/// Parameters of entries:
/// </summary>
/// <param name="MAT">Array with numeration of elements[0..N-1, 0..N-1]</param>
/// <param name="N">Dimension of matrix A</param>
public double[,] CofacMatrix(double[,] MAT, int N)
{
double[,] tmp = new double[N - 1, N - 1];
double[,] ResultMat = new double[N, N];
for (int RY = 0; RY < N; RY++)
{
for (int RX = 0; RX < N; RX++)
{
int XX = 0;
int YY = 0;
for (int y = 0; y < N; y++)
{
for (int x = 0; x < N; x++)
{
if (x != RY & y != RX)
{
tmp[XX, YY] = MAT[x, y];
XX++;
if (XX == N - 1)
{
XX = 0;
YY++;
}
}
}
}
MatrixDeterminant MatDet = new MatrixDeterminant();
ResultMat[RY, RX] = Math.Pow(-1, RX + RY + 2) * MatDet.MatrixDet(tmp, N - 1);
}
}
return(ResultMat);
}
