[petsc-users] Symmetric MPIAIJ matrix

[Bikash Kanungo]

Hi Matthew,

The entries to the last few rows of my matrix has non-local contributions
from a large number of processors. Since the matrix is symmetric, I need
not set the non-local entries in the last few rows as they are equal to
their transpose entries, which on the other hand are stored as local
entries in their respective processors.

Thanks,
Bikash

On Tue, Jul 7, 2015 at 4:25 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Tue, Jul 7, 2015 at 3:22 PM, Bikash Kanungo <bikash at umich.edu> wrote:
>
>> Hi,
>>
>> Is there a way to ignore the lower (or upper) triangular entries in an
>> MATMPIAIJ matrix when I know my matrix is symmetric? I can see a
>> MAT_SYMMETRIC option in MatSetOption, but I don't think it ignores any
>> lower (or upper) triangular entry.
>>
>
> Why do you want this?
>
>
>> I cannot use MATMPISBAIJ due to MatMatMult incompatibility with
>> MATMPIAIJ.
>>
>
> This is the only way. MatMatMult() is quite complex and there is no real
> advantage to ignoring
> the entries, so we have not implemented it here.
>
>   Matt
>
>
>> Thanks,
>> Bikash
>>
>> --
>> Bikash S. Kanungo
>> PhD Student
>> Computational Materials Physics Group
>> Mechanical Engineering
>> University of Michigan
>>
>>
>
>
> --
> 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
>



-- 
Bikash S. Kanungo
PhD Student
Computational Materials Physics Group
Mechanical Engineering
University of Michigan
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