[petsc-users] Accessing Vector's ghost values

[Max Rudolph]

Did you try running with -on_error_attach_debugger and and using your
debugger to try to figure out where your code is segfaulting?

Max

On Thu, Feb 23, 2012 at 10:07 AM, Bojan Niceno <bojan.niceno at psi.ch> wrote:

>  Thanks Ju.  I studied this case carefully, and it seems clear to me.
> When I apply the same techniques in my code, I get error messages I sent to
> my reply to Matthew.
>
>
>     Cheers,
>
>
>     Bojan
>
>
>
> On 2/23/2012 6:46 PM, Ju LIU wrote:
>
>
>
> 2012/2/23 Bojan Niceno <bojan.niceno at psi.ch>
>
>> Hi all,
>>
>> I've never used a mailing list before, so I hope this message will reach
>> PETSc users and experts and someone might be willing to help me.  I am also
>> novice in PETSc.
>>
>> I have developed an unstructured finite volume solver on top of PETSc
>> libraries.  In sequential, it works like a charm.  For the parallel
>> version, I do domain decomposition externally with Metis, and work out
>> local and global numberings, as well as communication patterns between
>> processor.  (The latter don't seem to be needed for PETSc, though.)  When I
>> run my program in parallel, it also works, but I miss values in vectors'
>> ghost points.
>>
>> I create vectors with command: VecCreate(PETSC_COMM_WORLD, &x);
>>
>> Is it possible to get the ghost values if a vector is created like this?
>>
>> I have tried to use VecCreateGhost, but for some reason which is beyond
>> my comprehension, PETSc goes berserk when it reaches the command:
>> VecCreateGhost(PETSC_COMM_WORLD, n, PETSC_DECIDE, nghost, ifrom, &x)
>>
>> Can anyone help me?  Either how to reach ghost values for vector created
>> by VecCreate, or how to use VecCreateGhost properly?
>>
>>
> http://www.mcs.anl.gov/petsc/petsc-current/src/vec/vec/examples/tutorials/ex9.c.html
> could be helpful.
>
>
>>   Bojan
>>
>
>
>
> --
>
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