[petsc-users] general VecScatter from MPI to MPI

[Ethan Coon]

So I thought I understood how VecScatters worked, but apparently not.
Is it possible to create a general VecScatter from an arbitrarily
partitioned (MPI) Vec to another arbitrarily partitioned (MPI) Vec with
the same global sizes (or same global IS sizes) but different local
sizes?  Shouldn't this just be a matter of relying upon the implied
LocalToGlobalMapping?

See below snippet (and its errors):

Ethan



Vec vA
Vec vB
VecScatter scatter_AB

PetscInt np
PetscInt rank
PetscErrorCode ierr

if (rank.eq.0) np = 3
if (rank.eq.1) np = 1

call VecCreateMPI(PETSC_COMM_WORLD, 2, PETSC_DETERMINE, vA, ierr)
call VecCreateMPI(PETSC_COMM_WORLD, np, PETSC_DETERMINE, vB, ierr)
 
call VecScatterCreate(vA, PETSC_NULL_OBJECT, vB, PETSC_NULL_OBJECT, 
	scatter_AB, ierr)

...

$> mpiexec -n 2 ./test

[0]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR: Nonconforming object sizes!
[0]PETSC ERROR: Local scatter sizes don't match!
[0]PETSC ERROR:
------------------------------------------------------------------------
[1]PETSC ERROR: --------------------- Error Message
------------------------------------
[1]PETSC ERROR: Nonconforming object sizes!
[1]PETSC ERROR: Local scatter sizes don't match!
[0]PETSC ERROR: Petsc Development HG revision:
5dbe1264252fb9cb5d8e033d620d18f7b0e9111f  HG Date: Fri Feb 11 15:44:04
2011 -0600
[0]PETSC ERROR: See docs/changes/index.html for recent updates.
[0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
[0]PETSC ERROR: See docs/index.html for manual pages.
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: ./test on a linux-gnu named tama1 by ecoon Thu Feb 17
08:14:57 2011
[0]PETSC ERROR: Libraries linked
from /packages/petsc/petsc-dev3.0-mpich2-local-gcc-4.3.3/debug-shared/lib
[0]PETSC ERROR: Configure run at Fri Feb 11 16:15:14 2011
[0]PETSC ERROR: Configure options --with-debugging=1
--prefix=/packages/petsc/petsc-dev3.0-mpich2-local-gcc-4.3.3/debug-shared --download-mpich=1 --download-ml=1 --download-umfpack=1 --with-blas-lapack-dir=/usr/lib --download-parmetis=yes PETSC_ARCH=linux-gnu-c-debug-shared --with-clanguage=c --download-hypre=1 --with-shared-libraries=1 --download-hdf5=1
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: VecScatterCreate() line 1432 in
src/vec/vec/utils/vscat.c
application called MPI_Abort(MPI_COMM_WORLD, 60) - process 0
[cli_0]: aborting job:
application called MPI_Abort(MPI_COMM_WORLD, 60) - process 0
[1]PETSC ERROR: APPLICATION TERMINATED WITH THE EXIT STRING: Hangup
(signal 1)




-- 
------------------------------------
Ethan Coon
Post-Doctoral Researcher
Applied Mathematics - T-5
Los Alamos National Laboratory
505-665-8289

http://www.ldeo.columbia.edu/~ecoon/
------------------------------------