LAPACK/ScaLAPACK Development

Hello,

Can I use LAPACK to find only the largest absolute eigenvalue of a matrix? If there is no single largest value, then the equal largest will do. I only require that largest absolute eigenvalue and was hoping to save time by not calculating the others.

Thanks.

The LAPACK expert-routines (s/d)syevx, (c/z)heevx allow to
calculate a selected range of Eigenvalues and optional Eigenvectors.

You can also look for code of the Lanczos-method, but these
LAPACK-routines are very very good.

Good luck,

Michael