[petsc-dev] petsc-dev: ASM with sbaij matrix and block size=1 broken?

Matthew Knepley knepley at gmail.com
Sat Nov 5 07:26:16 CDT 2011


On Sat, Nov 5, 2011 at 5:20 AM, Brad Aagaard <baagaard at usgs.gov> wrote:

> Jed,
>
> I assume you mean src/ksp/ksp/examples/**tutorials/ex2
> I have not yet been able to duplicate the error with this example. Do you
> know of any other test cases that might be appropriate?
>
> My PyLith simulation with -malloc and -malloc_debug flags chokes on line
> 933 of src/mat/impls/baij/mpi/**baijjob.c with a EXEC_BAD_ACCESS.
>
>
> 933               for (l=0; l<nzA; l++)   cols[imark+l] = cstart +
> cworkA[l];
>
> When the memory error happens at this line, the debugger shows
> l = 1400100
> imark = 0
> cstart = 0
> cworkA[l] = 0
> cols[imark+l] = -17958193
>
> The address of the bad memory access matches the address of cols[imark+l].
>

Brad, can you check C->rmap->bs when this happens? Since this is the only
thing that changes, I am guessing that
it might be 0, and then you can get the wrong 'proc' which cascades. Can I
run this here?

  Thanks,

      Matt


> Brad
>
>
>
> On 11/4/11 8:39 PM, Jed Brown wrote:
>
>> On Fri, Nov 4, 2011 at 21:30, Brad Aagaard <baagaard at usgs.gov
>> <mailto:baagaard at usgs.gov>> wrote:
>>
>>    Barry,
>>
>>    Sorry for the hg goof. Here is the changeset that I think is related
>>    to the problem.
>>
>>    http://petsc.cs.iit.edu/petsc/**__petsc-dev/rev/7782710e3f96<http://petsc.cs.iit.edu/petsc/__petsc-dev/rev/7782710e3f96>
>>
>>    <http://petsc.cs.iit.edu/**petsc/petsc-dev/rev/**7782710e3f96<http://petsc.cs.iit.edu/petsc/petsc-dev/rev/7782710e3f96>
>> >
>>
>>
>> If bs=1, then this doesn't change anything. As far as I know, it is not
>> possible to create an SBAIJ(1) with map->bs != 1. Can you find a way for
>> me to reproduce this? I see no problem with this, for example:
>>
>> mpiexec -n 4 ./ex2 -mat_type sbaij -pc_type asm
>>
>
>


-- 
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
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