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

[Jose E. Roman]

There are several examples in the SLEPc distribution that use shell matrices.
http://www.grycap.upv.es/slepc/documentation/current/src/eps/examples/tutorials/ex3.c.html
http://www.grycap.upv.es/slepc/documentation/current/src/eps/examples/tutorials/ex9.c.html
http://www.grycap.upv.es/slepc/documentation/current/src/eps/examples/tutorials/ex6f.F.html

See also section 8.2 of the users guide.
Jose



El 13/08/2014, a las 07:11, Satish Balay escribió:

> On Tue, 12 Aug 2014, Tijo Vazhappilly wrote:
> 
>> Hi Balay,
>> 
>> I am a new user to Slepc. Is there any option to give a external matrix-vector
>> subroutine to Slepc program or  include with in the Slepc code.
> 
> check MatShell in petsc
> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MATSHELL.html
> 
>> 
>> Our matrix is symmetric and very sparse (DVR basis)  for  the eigenvalue
>> problem.  It  is a 3dimensional matrix and in the current  implementation,
>> the full
>> matrix is not constructed for the diagonalization. We are using arpack in our
>> current code.
>> 
>> My test slepc program takes a lot of time as expected by building the full
>> matrix. It wasn't clear from the manual or examples about other options.
> 
> perhaps the matrix was not preallocated correctly.
> 
> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatSeqAIJSetPreallocation.html
> 
>> Thank you for your time.
>> 
>> Best,
>> Tijo
>> 
>> ps: If you want I could post this to the slepc mailing list.
> 
> cc:ing list. thats the better location to discuss issues.
> 
> Satish
>