[petsc-users] Example for MatMatMultSymbolic

[Hong Zhang]

Hannes,
Do you use petsc-3.3?
MatMtMult() might be buggy. We have updated MatMtMult() in petsc-dev.
Suggest testing your code using petsc-dev
(http://www.mcs.anl.gov/petsc/developers/index.html).

As Jed suggested, you would use MatMatMult() instead of
MatMatMultSymbolic() and MatMatMultNumeric().
However, we do have examples using the latter.
See petsc-dev/src/mat/examples/tests/ex93.c
which I updated to run in parallel.
https://bitbucket.org/petsc/petsc-dev/commits/37e8170f9464171541ac1e801921bf58

I tested ex93 with valgrind and got clean output.
If your code shows valgrind error with petsc-dev, please let us know.

Hong


On Tue, Jan 8, 2013 at 4:58 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> Typically you would use this, for which there are a few examples (at the
> bottom of the page).
>
> http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Mat/MatMatMult.html
>
> If that doesn't fix your problem, please set up a test case or at least give
> us verbose diagnostics.
>
>
>
> On Tue, Jan 8, 2013 at 8:26 AM, Johannes Huber <johannes.huber at unibas.ch>
> wrote:
>>
>> Hi,
>> I have a valgrind "invalid read" in MatGetBrowsOfAoCols_MPIAIJ in the
>> lines
>>  rvalues  = gen_from->values; /* holds the length of receiving row */
>>  svalues  = gen_to->values;   /* holds the length of sending row */
>> (and others, but that are the first). This function is called indirectly
>> via MatMatMultSymbolic.
>> All invalid reads apear in MatGetBrowsOfAoCols_MPIAIJ.
>> The calling sequence for the matrix factors are
>>   MatCreate(PETSC_COMM_WORLD,A);
>>   MatSetSizes(A,NumLocRows,NumLocCols,PETSC_DETERMINE,PETSC_DETERMINE);
>>   MatSetType(A,MATMPIAIJ);
>>   MatMPIAIJSetPreallocation(A,PETSC_NULL,nnz,PETSC_NULL,onz);
>>   MatSetValues(...);
>>   MatAssemblyBegin(...)
>>   MatAssemblyEnd(...)
>> and then a call to MatMatMultSymbolic.
>> I want the result matrix to be created. In the documentation I see, that
>> this happens, if I pass MAT_REUSE_MATRIX as scall, but how can I pass the
>> value, I don't the parameter.
>> Where can I find an example for MatMatMultSymbolic / MatMatMultNumeric?
>> Thanks,
>>     Hannes
>
>