[petsc-users] SIGSEGV in Superlu_dist

[Matthew Knepley]

On Wed, Aug 12, 2015 at 2:01 PM, Anthony Haas <aph at email.arizona.edu> wrote:

> Hi Hong,
>
> I have attached a schematic of my matrices. I solve a generalized EVP in
> shift-and-invert mode. As you will see, I have indeed a zero diagonal block
> in the matrices A and B (blocks 4,4). I guess I could just add the zero
> entries to the diagonal elements of A? Is that strictly necessary when
> using a direct (LU) solver? Can you please give me a short explanation of
> why empty diagonal blocks can be problematic?
>

Yes, the sparse numbering schemes use the location of the diagonal for
faster indexing in many places.

   Matt


> Is the patch still available at:
> https://bitbucket.org/petsc/petsc/commits/ceeba3afeff0c18262ed13ef92e2508ca68b0ecf
> ?
>
> Thanks again,
>
> Anthony
>
>
>
>
>
>
> On 08/12/2015 08:58 AM, Hong wrote:
>
>> Anthony,
>> I just patched petsc-maint branch.
>>
>> Your matrix Amat_binary.m has empty diagonal blocks. Most petsc solvers
>> require matrix diagonal entries to be allocated as 'non-zero', i.e., insert
>> zero values to these zero entries. I would suggest you add zeros to
>> Amat_binary.m during its buildup. This would enable petsc solvers, as well
>> as other packages.
>>
>> Again, thanks for bug reporting.
>>
>> Hong
>>
>>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20150812/1fbd1470/attachment.html>