public static RMatrix Adjoint(RMatrix mat)
{
if (!mat.IsSquared())
{
throw new Exception("The matrix must be squared!");
}
RMatrix ma = new RMatrix(mat.GetnRows, mat.GetnCols);
for (int i = 0; i < mat.GetnRows; i++)
{
for (int j = 0; j < mat.GetnCols; j++)
{
ma[i, j] = Math.Pow(-1, i + j) * (Determinant(Minor(mat, i, j)));
}
}
return(ma.GetTranspose());
}
public static double Determinant(RMatrix mat)
{
double result = 0.0;
if (!mat.IsSquared())
{
throw new Exception("The matrix must be squared!");
}
if (mat.GetnRows == 1)
{
result = mat[0, 0];
}
else
{
for (int i = 0; i < mat.GetnRows; i++)
{
result += Math.Pow(-1, i) * mat[0, i] *
Determinant(RMatrix.Minor(mat, 0, i));
}
}
return(result);
}
public static RVector Transform(RVector vec, RMatrix mat)
{
RVector result = new RVector(vec.GetVectorSize);
if (!mat.IsSquared())
{
throw new Exception("The matrix must be squared!");
}
if (mat.GetnRows != vec.GetVectorSize)
{
throw new Exception("The ndim of the vector must be equal"
+ " to the number of rows of the matrix!");
}
for (int i = 0; i < mat.GetnRows; i++)
{
result[i] = 0.0;
for (int j = 0; j < mat.GetnCols; j++)
{
result[i] += vec[j] * mat[j, i];
}
}
return(result);
}