public static Matrix Housv(Matrix x)
{
if (!x.Any())
{
return(x);
}
double m = MatrixUtil.Max(MatrixUtil.Abs(x));
Matrix u = x / m;
double su = Math.Sign(u[0, 0]);
u[0, 0] = u[0, 0] + su * Norm1D(u);
return(u / Norm1D(u));
}