[petsc-users] is something wrong with nnz ?

[Manuel Ricardo Perez Cerquera]

Hi ,

I had the same problem some days ago, be careful about the KIND size of the
variables, when variables KINDS you pass to the functions
are different from the KINDS of the dummy variables of the functions,
yields in these kind of problems.

Cheers ! Manuel.

2011/11/23 jean-frederic thebault <jean-frederic at thebault-net.com>

> Well, actually, when I call MatSetFromOption, with the right arguments,
> the whole simulation is running, but there are some PETSC-ERROR about nnz,
> and when I comment the calling of MatSetFromOption, the simulation
> (program) stop at the first calculation. This time, I'm putting in this
> email the log-file with calling of MatSetFromOption (then with PETSC-ERROR
> on nnz)...
>
> Le 23 novembre 2011 17:17, Satish Balay <balay at mcs.anl.gov> a écrit :
>
> Since you get a SEGV - I would suggest running the code in the
>> debugger - to check where its crashing.
>>
>> Also run with valgrind to see where problems start.. Mostlikely the
>> issues would be change in prototypes for PETSc functions - between
>> releases.
>>
>> Satish
>>
>> On Wed, 23 Nov 2011, jean-frederic thebault wrote:
>>
>> > Thanks for your response.
>> >
>> > Sorry about that, to reduce the size of the log file, unfortunetly, I
>> did
>> > took out the bad lines... In the out.log I've put in this email, I've
>> make
>> > sure there are...
>> >
>> > Actually, I don't use MatSetOption, but MatSetFromOption instead.
>> However,
>> > when I called MatSetFromOption, the PETSC_COMM_WORLD was missing. But
>> now,
>> > it's getting worse !! (as you could see in the out.log included in this
>> > email).
>> >
>> > Le 23 novembre 2011 15:55, Jed Brown <jedbrown at mcs.anl.gov> a écrit :
>> >
>> > >  On Wed, Nov 23, 2011 at 08:24, jean-frederic thebault <
>> > > jean-frederic at thebault-net.com> wrote:
>> > >
>> > >> I'm wondering what's wrong in my code. I'm using PETSc to solve a
>> linear
>> > >> system, and willing to use a multi-processor computer. 9 years ago,
>> I used
>> > >> petsc-2.1.3 with success. Few weeks ago, I've update petsc with the
>> 3.1-p8
>> > >> version and made the necessary changes to work with. No problem. And
>> > >> recently, I've migrate to petsc-3.2-p5. Compilation is OK. But when
>> I do
>> > >> simulation, now, I have some PETSC-ERROR in the log file, even using
>> only
>> > >> one processor (see the out.log file in this email).
>> > >>
>> > >
>> > > You are calling MatSetOption() with the wrong number of arguments. C
>> > > compilers tell you about this, but Fortran compilers do not.
>> > >
>> > >
>> > >
>> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatSetOption.html
>> > >
>> > >
>> > >> However, I think I defined MatMPI and VecMPI correctly, according to
>> the
>> > >> doc. The log file tell that something wrong with the nnz which
>> should not
>> > >> be greater than row length (??).
>> > >>
>> > >
>> > > The log you sent does not say anything about nnz. Fix the call to
>> > > MatSetOption().
>> > >
>> > >  And also, with the previous version of PETSc I've used, the were no
>> > >> problem using -pc_type bjacobi and -sub_pc_type sor, juste to solve
>> linear
>> > >> system doing parallel computations and because SOR is not
>> parallelized. But
>> > >> now, when I use -pc_type bjacobi and -sub_pc_type sor, with 3 rank, I
>> > >> experiment some convergence problem during my simulation.
>> > >>
>> > >
>> > > These options should do the same thing they used to do. Make sure you
>> are
>> > > assembling correctly. If it's still confusing, run the old and new
>> code with
>> > >
>> > > -ksp_monitor_true_residual -ksp_converged_reason -ksp_view -pc_type
>> > > bjacobi -sub_pc_type sor
>> > >
>> > > and send the output of both for us to look at.
>> > >
>> > > Also note that you can use -pc_type sor even in parallel. There are
>> > > options for local iterations and full iterations.
>> > >
>> >
>>
>
>


-- 
Eng. Manuel Ricardo Perez Cerquera. MSc. Ph.D student
Antenna and EMC Lab (LACE)
Istituto Superiore Mario Boella (ISMB)
Politecnico di Torino
Via Pier Carlo Boggio 61, Torino 10138, Italy
Email: manuel.perezcerquera at polito.it
Phone: +39 0112276704
Fax: +39 011 2276 299
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