[petsc-users] ISCreateStride and MatGetSubmatrices

[Matthew Knepley]

On Tue, Aug 28, 2012 at 10:48 AM, shu guo <greatgs2008 at gmail.com> wrote:

> I am using totalview instead of  Valgrind. Where can I find the
> information of the stack trace?... Sorry about this easy question, I
> am really a beginner in programming...
>

'where'

   Matt


> Shu
>
> On Tue, Aug 28, 2012 at 11:44 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> > On Tue, Aug 28, 2012 at 10:42 AM, shu guo <greatgs2008 at gmail.com> wrote:
> >>
> >> Hi Jed,
> >>
> >> I was thinking about this issue either. But when I create the matrix,
> >> I hardcoded as
> >>
> >>           call MatCreateMPIBAIJ  (PETSC_COMM_WORLD,4,32,32,
> >>      &                          PETSC_DETERMINE, PETSC_DETERMINE,
> >>      &                          PETSC_NULL_INTEGER, mr(np(246)),
> >>      &                          PETSC_NULL_INTEGER, mr(np(247)),
> >>      &                          Kmatem, ierr)
> >>
> >> And it works good. Does that mean this should not be a concern as you
> >> mentioned?
> >
> >
> > Probably, but it's still bad practice when using Fortran, and it will
> cause
> > problems if you change the integer size later (e.g. to solve problems
> with
> > more than 2B degrees of freedom). What does Valgrind say?
> >
> >>
> >>
> >> Thanks.
> >>
> >> Shu
> >>
> >>
> >>
> >> On Tue, Aug 28, 2012 at 11:37 AM, Jed Brown <jedbrown at mcs.anl.gov>
> wrote:
> >> > On Tue, Aug 28, 2012 at 10:33 AM, shu guo <greatgs2008 at gmail.com>
> wrote:
> >> >>
> >> >> Dear All,
> >> >>
> >> >> I want to extract a sequential matrix from a MPIBAIJ matrix A with a
> >> >> dimension of 4n*4n. After assembly A, I use ISCreateStride to define
> >> >> the index by
> >> >>
> >> >>           call ISCreateStride(PETSC_COMM_WORLD,n,0,1,isrow,ierr)
> >> >
> >> >
> >> > Fortran does not do type conversion without interfaces (which are
> about
> >> > as
> >> > much hassle as benefit). If you configured PETSc with non-default
> >> > integer
> >> > sizes, be sure to declare PetscInt zero,one instead of using numeric
> >> > literals.
> >> >
> >> > Otherwise, run in valgrind to check that there isn't earlier
> corruption
> >> > and
> >> > run in a debugger to get a stack trace.
> >> >
> >> >>
> >> >>
> >> >> And extract the matrix as
> >> >>           call MatGetSubMatrices(Kmatem,1,isrow,isrow,
> >> >>      &                           MAT_INITIAL_MATRIX,Kmatemseq)
> >> >>
> >> >> But it gives me a segmentation fault when I call ISCreateStride. Is
> >> >> there anything I did wrong? Thanks for any advice.
> >> >>
> >> >> Shu
> >> >
> >> >
> >
> >
>



-- 
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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