[petsc-users] reduce a MPIBAIJ matrix to seqaij format

[shu guo]

Hi Hong,

Thanks for reply. I have a question on superlu_dist. Is this solver
suitable for ill-conditioned matrix? I read some thread of past
mailing list, Barry indicated that superlu is more adaptive with ill
conditioned matrix. Thanks.

Shu

On Mon, Aug 27, 2012 at 12:34 PM, Hong Zhang <hzhang at mcs.anl.gov> wrote:
> shu guo :
>>
>>
>> I am a new user of PetSc in fortran. I want to solve a ill conditioned
>> matrix right now. And the matrix is now assembled as a MPIBAIJ matrix
>> in a paralleled way. Now I want to use superlu (the serial direct
>> solver) to solve it since its ill-conditioned characteristic. I tried
>> MatConvert as
>>
>>           call MatConvert (Kmatem, MATSEQAIJ, MAT_INITIAL_MATRIX,
>> Kmatemseq)
>> and it gives me a segmentation error. Can anyone give me some advice?
>
>
>  call MatConvert (Kmatem, MATAIJ, MAT_INITIAL_MATRIX, Kmatemseq)
> or
> call MatConvert (Kmatem, MATMPIAIJ, MAT_INITIAL_MATRIX, Kmatemseq)
>>
>>
>> BTW, I am using Petsc 2.3.3-p15 version, which do not have Schur
>> preconditioner for ill-conditioned matrix. Also hope someone can give
>> me some advice on how to solve this kind of matrix based on this petsc
>> version. Thanks a lot!
>
>
> Petsc 2.3.3-p15 is too old. Please update to the latest petsc-3.3 and
> configure it
> with '--download-metis --download-parmetis --download-superlu
> --download-superlu_dist'
> Then use superlu_dist direct solver.
>
> Hong
>>
>>
>> Shu
>
>