2012/2/23 Bojan Niceno <bojan.niceno@psi.ch>

Hi all,

I've never used a mailing list before, so I hope this message will reach PETSc users and experts and someone might be willing to help me.  I am also novice in PETSc.

I have developed an unstructured finite volume solver on top of PETSc libraries.  In sequential, it works like a charm.  For the parallel version, I do domain decomposition externally with Metis, and work out local and global numberings, as well as communication patterns between processor.  (The latter don't seem to be needed for PETSc, though.)  When I run my program in parallel, it also works, but I miss values in vectors' ghost points.

I create vectors with command: VecCreate(PETSC_COMM_WORLD, &x);

Is it possible to get the ghost values if a vector is created like this?

I have tried to use VecCreateGhost, but for some reason which is beyond my comprehension, PETSc goes berserk when it reaches the command: VecCreateGhost(PETSC_COMM_WORLD, n, PETSC_DECIDE, nghost, ifrom, &x)

Can anyone help me?  Either how to reach ghost values for vector created by VecCreate, or how to use VecCreateGhost properly?

http://www.mcs.anl.gov/petsc/petsc-current/src/vec/vec/examples/tutorials/ex9.c.html  could be helpful.

  Bojan

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