[petsc-users] check for NULL pointer in VecCreateGhost

[Mohammad Mirzadeh]

Matt, I'm just trying to understand what is going on and why the things do
what they do -- I'm not asking for anything in particular :). I just
thought that the situation for VecCreateGhost and AOXXXXToYYYY are somewhat
similar here and was surprised to see one crashes on NULL while the other
one does not.

I have included a check on the pointer and size for AO calls and just
wanted to check if I need the same thing with VecCreateGhost if there is
such an internal check.

Mohammad


On Mon, Feb 20, 2012 at 4:10 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Mon, Feb 20, 2012 at 5:58 PM, Mohammad Mirzadeh <mirzadeh at gmail.com>wrote:
>
>> Just if wondering what the actual code is, here's the bit causing the
>> trouble:
>>
>> AOApplicationToPetsc(ao, ghostNodes.size(), (int*)ghostNodes);
>> VecCreateGhost(comm, localNodes.size(), PETSC_DECIDE, ghostNodes.size(),
>> (int*)ghostNodes, &v);
>> AOPetscToApplication(ao, ghostNodes.size(), (int*)ghostNodes);
>>
>> when the code is in serial, ghostNodes.size() = 0 and (int*)ghostNodes =
>> NULL.
>>
>
> So you are asking us to give up checking for NULL if the size is 0?
>
>    Matt
>
>
>> On Mon, Feb 20, 2012 at 3:54 PM, Mohammad Mirzadeh <mirzadeh at gmail.com>wrote:
>>
>>> Sure, Jed. My bad. Here's the whole message when the code is run in
>>> _serial_:
>>>
>>> [0]PETSC ERROR: --------------------- Error Message
>>> ------------------------------------
>>> [0]PETSC ERROR: Invalid pointer!
>>> [0]PETSC ERROR: Null Pointer: Parameter # 3!
>>> [0]PETSC ERROR:
>>> ------------------------------------------------------------------------
>>> [0]PETSC ERROR: Petsc Release Version 3.2.0, Patch 6, Wed Jan 11
>>> 09:28:45 CST 2012
>>> [0]PETSC ERROR: See docs/changes/index.html for recent updates.
>>> [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
>>> [0]PETSC ERROR: See docs/index.html for manual pages.
>>> [0]PETSC ERROR:
>>> ------------------------------------------------------------------------
>>> [0]PETSC ERROR: ./petsc on a arch-linu named mohammad-laptop by mohammad
>>> Mon Feb 20 15:52:25 2012
>>> [0]PETSC ERROR: Libraries linked from
>>> /home/mohammad/soft/petsc-3.2-p6/arch-linux2-cxx-debug/lib
>>> [0]PETSC ERROR: Configure run at Thu Feb 16 02:16:40 2012
>>> [0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++
>>> --with-fc=gfortran --with-clanguage=cxx --download-f-blas-lapack=1
>>> --download-mpich=1 --download-hypre=1 --download-ml=1
>>> --with-parmetis-include=/home/mohammad/soft/parmetis/include
>>> --with-parmetis-lib="-L/home/mohammad/soft/parmetis/lib -lparmetis -lmetis"
>>> --download-superlu_dist=1
>>> [0]PETSC ERROR:
>>> ------------------------------------------------------------------------
>>> [0]PETSC ERROR: AOApplicationToPetsc() line 249 in
>>> /home/mohammad/soft/petsc-3.2-p6/src/dm/ao/interface/ao.c
>>> [0]PETSC ERROR: --------------------- Error Message
>>> ------------------------------------
>>> [0]PETSC ERROR: Invalid pointer!
>>> [0]PETSC ERROR: Null Pointer: Parameter # 3!
>>> [0]PETSC ERROR:
>>> ------------------------------------------------------------------------
>>> [0]PETSC ERROR: Petsc Release Version 3.2.0, Patch 6, Wed Jan 11
>>> 09:28:45 CST 2012
>>> [0]PETSC ERROR: See docs/changes/index.html for recent updates.
>>> [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
>>> [0]PETSC ERROR: See docs/index.html for manual pages.
>>> [0]PETSC ERROR:
>>> ------------------------------------------------------------------------
>>> [0]PETSC ERROR: ./petsc on a arch-linu named mohammad-laptop by mohammad
>>> Mon Feb 20 15:52:25 2012
>>> [0]PETSC ERROR: Libraries linked from
>>> /home/mohammad/soft/petsc-3.2-p6/arch-linux2-cxx-debug/lib
>>> [0]PETSC ERROR: Configure run at Thu Feb 16 02:16:40 2012
>>> [0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++
>>> --with-fc=gfortran --with-clanguage=cxx --download-f-blas-lapack=1
>>> --download-mpich=1 --download-hypre=1 --download-ml=1
>>> --with-parmetis-include=/home/mohammad/soft/parmetis/include
>>> --with-parmetis-lib="-L/home/mohammad/soft/parmetis/lib -lparmetis -lmetis"
>>> --download-superlu_dist=1
>>> [0]PETSC ERROR:
>>> ------------------------------------------------------------------------
>>> [0]PETSC ERROR: AOPetscToApplication() line 210 in
>>> /home/mohammad/soft/petsc-3.2-p6/src/dm/ao/interface/ao.c
>>>
>>>
>>> It seems to complain about the 3rd parameter of AOApplicationToPetsc()
>>> and AOPetscToApplication(). VecCreateGhost, on the other hand, is fine.
>>>
>>> On Mon, Feb 20, 2012 at 3:47 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
>>>
>>>> On Mon, Feb 20, 2012 at 17:25, Mohammad Mirzadeh <mirzadeh at gmail.com>wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> Is there an internal check to see if the 'ghost' pointer in
>>>>> VecCreateGhost() is NULL ? This can happen, for example, if the code is run
>>>>> in serial and the there are no ghost points (hence n_ghost = 0 and ghost =
>>>>> NULL(implementation dependent of course) ). AOXXXXToYYYY functions seem to
>>>>> crash if the corresponding pointer is NULL.
>>>>>
>>>>
>>>> Always send the whole error message.
>>>>
>>>
>>>
>>
>
>
> --
> 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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