[petsc-users] is something wrong with nnz ?

[Satish Balay]

> [1]PETSC ERROR: d_nnz cannot be less than 0: local row 78 value -750763693!

There is something wrong in your code. You'll have to verify the
prototypes of all functions - with the petsc-3.2 documentation.

And valgrind is an easy way to pinpoint to the problem source. [also a
debugger should show you whats going wrong]

Satish


On Wed, 23 Nov 2011, jean-frederic thebault wrote:

> 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.
> > > >
> > >
> >
>