[MOAB-dev] Parallel read issues: mbconvert vs mbparallelcomm_test (PARALLEL_RESOLVE_SHARED_ENTS)

[Dmitry Karpeev]

Hi,
It appears that some of the problems I had earlier with reading meshes
in parallel have to do with
the resolution of shared entities.  mbconvert typically read the files
in without a problem, while mbparallelcomm_test
refused to read some files and not others, etc (it was confusing).

I stripped off most of the mbconvert code to make a simple
benchmarking tool (tools/mbparread).
Unlike mbparallelcomm_test, mbparread (and mbconvert, from which it
derives) does not set any parallel reader
options by default.  When reintroducing them one by one, I stumbled
upon the following issue:
feeding PARALLEL_RESOLVE_SHARED_ENTS can cause mbparread to fail.
It appears that problems are more complicated when reading
tjunc6RIB_16.h5m, but with blocks-64.h5m
it is more straightforward (this is a 2 proc version on my laptop):

With PARALLEL=BCAST:
------------------------------------------------------------------------------------------------------------------------------------------------------
[hal Mon Apr 05 05:37 PM] ~/fathom/moab/trunk
>$MPI2_PREFIX/bin/mpiexec -n 2
/home/karpeev/fathom/moab/unstable/build/tools/mbparread -O
PARTITION_DISTRIBUTE -O CPUTIME -O PARTITION=MATERIAL_SET -O
PARALLEL=BCAST /home/karpeev/fathom/moab/data/blocks-64.h5m
Read times: 0.448433 0.00270009 5.96046e-06 0.892087 (PARALLEL
READ/PARALLEL CHECK_GIDS_SERIAL/PARALLEL GET_FILESET_ENTS/PARALLEL
BROADCAST/)
[proc 0 of 2]: Read "/home/karpeev/fathom/moab/data/blocks-64.h5m"
[proc 1 of 2]: Read "/home/karpeev/fathom/moab/data/blocks-64.h5m"

With PARALLEL=BCAST and PARALLEL_RESOLVE_SHARED_ENTS
------------------------------------------------------------------------------------------------------------------------------------------------------
[hal Mon Apr 05 05:38 PM] ~/fathom/moab/trunk
>$MPI2_PREFIX/bin/mpiexec -n 2
/home/karpeev/fathom/moab/unstable/build/tools/mbparread -O
PARTITION_DISTRIBUTE -O CPUTIME -O PARTITION=MATERIAL_SET -O
PARALLEL=BCAST -O PARALLEL_RESOLVE_SHARED_ENTS
/home/karpeev/fathom/moab/data/blocks-64.h5m
Failed to load "/home/karpeev/fathom/moab/data/blocks-64.h5m".
Error code: MB_ENTITY_NOT_FOUND (4)
Error message: Failed in step PARALLEL RESOLVE_SHARED_ENTS


Failed to load "/home/karpeev/fathom/moab/data/blocks-64.h5m".
Error code: MB_ENTITY_NOT_FOUND (4)
Error message: Failed in step PARALLEL RESOLVE_SHARED_ENTS
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

The other read modes (BCAST_DELETE, READ_DELETE, READ_PART) appear to
work fine with and without PARALLEL_RESOLVE_SHARED_ENTS.
Any ideas what may be going on?
The mesh files I used can be found in ~karpeev/fathom/moab/data on MCS
machines and on cosmea.

Thanks.
Dmitry.