On Thu, Feb 17, 2011 at 10:06 AM, Ethan Coon <span dir="ltr"><<a href="mailto:ecoon@lanl.gov">ecoon@lanl.gov</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
So I thought I understood how VecScatters worked, but apparently not.<br>
Is it possible to create a general VecScatter from an arbitrarily<br>
partitioned (MPI) Vec to another arbitrarily partitioned (MPI) Vec with<br>
the same global sizes (or same global IS sizes) but different local<br>
sizes? Shouldn't this just be a matter of relying upon the implied<br>
LocalToGlobalMapping?<br></blockquote><div><br></div><div>No, the way you have to do this is to map a global Vec to a bunch of</div><div>sequential local Vecs with the sizes you want. This is also how we map</div><div>to overlapping arrays.</div>
<div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
See below snippet (and its errors):<br>
<br>
Ethan<br>
<br>
<br>
<br>
Vec vA<br>
Vec vB<br>
VecScatter scatter_AB<br>
<br>
PetscInt np<br>
PetscInt rank<br>
PetscErrorCode ierr<br>
<br>
if (rank.eq.0) np = 3<br>
if (rank.eq.1) np = 1<br>
<br>
call VecCreateMPI(PETSC_COMM_WORLD, 2, PETSC_DETERMINE, vA, ierr)<br>
call VecCreateMPI(PETSC_COMM_WORLD, np, PETSC_DETERMINE, vB, ierr)<br>
<br>
call VecScatterCreate(vA, PETSC_NULL_OBJECT, vB, PETSC_NULL_OBJECT,<br>
scatter_AB, ierr)<br>
<br>
...<br>
<br>
$> mpiexec -n 2 ./test<br>
<br>
[0]PETSC ERROR: --------------------- Error Message<br>
------------------------------------<br>
[0]PETSC ERROR: Nonconforming object sizes!<br>
[0]PETSC ERROR: Local scatter sizes don't match!<br>
[0]PETSC ERROR:<br>
------------------------------------------------------------------------<br>
[1]PETSC ERROR: --------------------- Error Message<br>
------------------------------------<br>
[1]PETSC ERROR: Nonconforming object sizes!<br>
[1]PETSC ERROR: Local scatter sizes don't match!<br>
[0]PETSC ERROR: Petsc Development HG revision:<br>
5dbe1264252fb9cb5d8e033d620d18f7b0e9111f HG Date: Fri Feb 11 15:44:04<br>
2011 -0600<br>
[0]PETSC ERROR: See docs/changes/index.html for recent updates.<br>
[0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.<br>
[0]PETSC ERROR: See docs/index.html for manual pages.<br>
[0]PETSC ERROR:<br>
------------------------------------------------------------------------<br>
[0]PETSC ERROR: ./test on a linux-gnu named tama1 by ecoon Thu Feb 17<br>
08:14:57 2011<br>
[0]PETSC ERROR: Libraries linked<br>
from /packages/petsc/petsc-dev3.0-mpich2-local-gcc-4.3.3/debug-shared/lib<br>
[0]PETSC ERROR: Configure run at Fri Feb 11 16:15:14 2011<br>
[0]PETSC ERROR: Configure options --with-debugging=1<br>
--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<br>
[0]PETSC ERROR:<br>
------------------------------------------------------------------------<br>
[0]PETSC ERROR: VecScatterCreate() line 1432 in<br>
src/vec/vec/utils/vscat.c<br>
application called MPI_Abort(MPI_COMM_WORLD, 60) - process 0<br>
[cli_0]: aborting job:<br>
application called MPI_Abort(MPI_COMM_WORLD, 60) - process 0<br>
[1]PETSC ERROR: APPLICATION TERMINATED WITH THE EXIT STRING: Hangup<br>
(signal 1)<br>
<br>
<br>
<br>
<br>
--<br>
------------------------------------<br>
Ethan Coon<br>
Post-Doctoral Researcher<br>
Applied Mathematics - T-5<br>
Los Alamos National Laboratory<br>
505-665-8289<br>
<br>
<a href="http://www.ldeo.columbia.edu/~ecoon/" target="_blank">http://www.ldeo.columbia.edu/~ecoon/</a><br>
------------------------------------<br>
<br>
</blockquote></div><br><br clear="all"><br>-- <br>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener<br>