Re: [ublas] bindings for syevd, heevd, syevx and heevx

From: Thomas Klimpel (Thomas.Klimpel_at_[hidden])
Date: 2008-05-01 16:53:04

Hi Nico,

> Awesome! Am I correct in assuming that the difference between
> these bindings and the syev bindings that were already in the
> lapack bindings is that syevd allows for partial eigenvalue
> decomposition (as opposed to computing all eigenvalues/vectors at once)?

syevd uses a (hopefully fast) "divide and conquer" algorithm, and therefore needs an additional integer workspace. syevx is an "expert" driver routine, that allows for partial eigenvalue decomposition. I normally use www.netlib.org/lapack/lapackqref.ps to find the simple and expert driver routines.

In case I know the name of the routine, http://www.netlib.org/lapack/explore-html/ allows me to browse the documented fortran sources. This documentation is also included in the lapack-3.1.1 tarball in the html subdirectory.

Regards,
Thomas