// Function to calculate and store inverse, returns false if Matrix is singular
public MatrixSlow Inverse()
{
int N = InnerMatrix.GetUpperBound(0) + 1;
double[,] inverse = new double[N, N];
// Find determinant of A[][]
double det = Determinant(InnerMatrix, N);
if (det == 0)
{
throw new Exception("Singular Matrix, can't find its inverse");
}
// Find adjoint
double[,] adj = Adjoint(InnerMatrix);
// Find Inverse using formula "inverse(A) = adj(A)/det(A)"
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
{
inverse[i, j] = adj[i, j] / det;
}
}
return(MatrixSlow.CreateWithArray(inverse));
}
public static MatrixSlow CreateWithArray(double[,] arr)
{
MatrixSlow m = new MatrixSlow();
m._Row = arr.GetUpperBound(0) + 1;
m._Column = arr.GetUpperBound(1) + 1;
m.InnerMatrix = arr;
return(m);
}
public static MatrixSlow Create(int a, int b)
{
MatrixSlow m = new MatrixSlow();
m._Row = a;
m._Column = b;
m.InnerMatrix = new double[a, b];
return(m);
}
public MatrixSlow Transpose()
{
double[,] transpose = new double[_Column, _Row];
for (int i = 0; i < _Row; i++)
{
for (int j = 0; j < _Column; j++)
{
transpose[j, i] = InnerMatrix[i, j];
}
}
return(MatrixSlow.CreateWithArray(transpose));
}
public static MatrixSlow operator *(MatrixSlow a, MatrixSlow b)
{
if (a._Column != b._Row)
{
throw new Exception("Dimension mismatch");
}
MatrixSlow c = MatrixSlow.Create(a._Row, b._Column);
for (int i = 0; i < c._Row; i++)
{
for (int j = 0; j < c._Column; j++)
{
c.InnerMatrix[i, j] = 0;
for (int k = 0; k < b._Row; k++)
{
c.InnerMatrix[i, j] += a.InnerMatrix[i, k] * b.InnerMatrix[k, j];
}
}
}
return(c);
}
