[petsc-users] slepc external matrix-vector product subroutine

[Barry Smith]

On Aug 16, 2014, at 11:08 AM, tijovaz <tijovaz at pitt.edu> wrote:

> Hi,
> 
> Preallocation of the matrix greatly improved the speed up of the eigensolver.
> 
> 
> Is it possible to use the lapack routine 'DSPMV' in the external matrix-vector multiplication for the shellmatrix ?
> I couldn't find this routine in the petscblaslapack.h or slepcblaslapack.h.  Am I missing something?

  You can use it since it is part of BLAS and is linked into the executable. The petscblaslapack.h and slepcblaslapack.h only have prototypes for the functions we use directly in PETSc/SLEPc.  You just have to write your own prototype for it.

   Barry

> 
> If there is a slepc/petsc matrix-vector multiplication routine that would also work.
> 
> Thanks,
> Tijo
> 
>