Hi Toby,

can you try with a fully distributed vector (without ghost values)
instead? Does that work?

On Wed, Jul 25, 2012 at 9:45 AM, Toby D. Young <[email protected]> wrote:
>
>
> Greetings,
>
> I am running an application based on the step-40 distributed model.
> I would like to perform the operation <v,Au> (vector-matrix-vector
> multiplication). At the end of solve () function I have added:
> const double
> norm=system_matrix.matrix_scalar_product(locally_relevant_solution,locally_relevant_solution);
> which works fine if (n_mpi_processes==1).
>
> How can this be done with n_mpi_processes>1?
>
> The (truncated) error message I get is:
>
> [1]PETSC ERROR: --------------------- Error Message
> ------------------------------------ [0]PETSC ERROR: [1]PETSC ERROR:
> Nonconforming object sizes! [1]PETSC ERROR: Mat mat,Vec y: local dim
> 4160 8450! [1]PETSC ERROR:
> ------------------------------------------------------------------------
> [1]PETSC ERROR: MatMult() line 2083
> in /home/tyoung/research.dev/petsc-dev/src/mat/interface/matrix.c
> ---------------------------------------------------- Exception on
> processing: --------------------------------------------------------
> An error occurred in line <512> of file
> </home/tyoung/research.dev/deal.II/source/lac/petsc_matrix_base.cc> in
> function void
> dealii::PETScWrappers::MatrixBase::vmult(dealii::PETScWrappers::VectorBase&,
> const dealii::PETScWrappers::VectorBase&) const The violated condition
> was: ierr == 0 The name and call sequence of the exception was:
> ExcPETScError(ierr) Additional Information:
> An error with error number 60 occurred while calling a PETSc function
> --------------------------------------------------------
>
> Confused. I am not sure how to deal with this.
>
> Why is the locally_relevant_solution.size () and
> ()completely_distributed_solution.size () reported to be twice the size
> of the distributed matrix? Are the vectors not distributed?
>
> viz. PETSC ERROR: Mat mat,Vec y: local dim 4160 8450 (on two processes).
>
> Any ideas please?
>
> Best,
>         Toby
>
>
>
>
> --
> Toby D. Young
>
> Assistant Professor Philosophy & Physics
> Polish Academy of Sciences
> www:   http://www.ippt.gov.pl/~tyoung
> skype: stenografia
>
> _______________________________________________
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-- 
Timo Heister
http://www.math.tamu.edu/~heister/
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