[petsc-users] [beginner question] Different communicators in the two objects: Argument # 1 and 2 flag 3!

Niklas Fischer niklas at niklasfi.de
Tue Apr 22 07:59:40 CDT 2014


I should probably note that everything is fine if I run the serial 
version of this (with the exact same matrix + right hand side).

PETSc KSPSolve done, residual norm: 3.13459e-13, it took 6 iterations.

Am 22.04.2014 14:12, schrieb Niklas Fischer:
>
> Am 22.04.2014 13:57, schrieb Matthew Knepley:
>> On Tue, Apr 22, 2014 at 6:48 AM, Niklas Fischer <niklas at niklasfi.de 
>> <mailto:niklas at niklasfi.de>> wrote:
>>
>>     Am 22.04.2014 13:08, schrieb Jed Brown:
>>
>>         Niklas Fischer <niklas at niklasfi.de
>>         <mailto:niklas at niklasfi.de>> writes:
>>
>>             Hello,
>>
>>             I have attached a small test case for a problem I am
>>             experiencing. What
>>             this dummy program does is it reads a vector and a matrix
>>             from a text
>>             file and then solves Ax=b. The same data is available in
>>             two forms:
>>               - everything is in one file (matops.s.0 and vops.s.0)
>>               - the matrix and vector are split between processes
>>             (matops.0,
>>             matops.1, vops.0, vops.1)
>>
>>             The serial version of the program works perfectly fine
>>             but unfortunately
>>             errors occure, when running the parallel version:
>>
>>             make && mpirun -n 2 a.out matops vops
>>
>>             mpic++ -DPETSC_CLANGUAGE_CXX -isystem
>>             /home/data/fischer/libs/petsc-3.4.3/arch-linux2-c-debug/include
>>             -isystem
>>             /home/data/fischer/libs/petsc-3.4.3/include petsctest.cpp
>>             -Werror -Wall
>>             -Wpedantic -std=c++11 -L
>>             /home/data/fischer/libs/petsc-3.4.3/arch-linux2-c-debug/lib
>>             -lpetsc
>>             /usr/bin/ld: warning: libmpi_cxx.so.0, needed by
>>             /home/data/fischer/libs/petsc-3.4.3/arch-linux2-c-debug/lib/libpetsc.so,
>>             may conflict with libmpi_cxx.so.1
>>             /usr/bin/ld: warning: libmpi.so.0, needed by
>>             /home/data/fischer/libs/petsc-3.4.3/arch-linux2-c-debug/lib/libpetsc.so,
>>             may conflict with libmpi.so.1
>>             librdmacm: couldn't read ABI version.
>>             librdmacm: assuming: 4
>>             CMA: unable to get RDMA device list
>>             --------------------------------------------------------------------------
>>             [[43019,1],0]: A high-performance Open MPI point-to-point
>>             messaging module
>>             was unable to find any relevant network interfaces:
>>
>>             Module: OpenFabrics (openib)
>>                Host: dornroeschen.igpm.rwth-aachen.de
>>             <http://dornroeschen.igpm.rwth-aachen.de>
>>             CMA: unable to get RDMA device list
>>
>>         It looks like your MPI is either broken or some of the code
>>         linked into
>>         your application was compiled with a different MPI or
>>         different version.
>>         Make sure you can compile and run simple MPI programs in
>>         parallel.
>>
>>     Hello Jed,
>>
>>     thank you for your inputs. Unfortunately MPI does not seem to be
>>     the issue here. The attachment contains a simple MPI hello world
>>     program which runs flawlessly (I will append the output to this
>>     mail) and I have not encountered any problems with other MPI
>>     programs. My question still stands.
>>
>>
>> This is a simple error. You created the matrix A using 
>> PETSC_COMM_WORLD, but you try to view it
>> using PETSC_VIEWER_STDOUT_SELF. You need to use 
>> PETSC_VIEWER_STDOUT_WORLD in
>> order to match.
>>
>>   Thanks,
>>
>>      Matt
>>
>>     Greetings,
>>     Niklas Fischer
>>
>>     mpirun -np 2 ./mpitest
>>
>>     librdmacm: couldn't read ABI version.
>>     librdmacm: assuming: 4
>>     CMA: unable to get RDMA device list
>>     --------------------------------------------------------------------------
>>     [[44086,1],0]: A high-performance Open MPI point-to-point
>>     messaging module
>>     was unable to find any relevant network interfaces:
>>
>>     Module: OpenFabrics (openib)
>>       Host: dornroeschen.igpm.rwth-aachen.de
>>     <http://dornroeschen.igpm.rwth-aachen.de>
>>
>>     Another transport will be used instead, although this may result in
>>     lower performance.
>>     --------------------------------------------------------------------------
>>     librdmacm: couldn't read ABI version.
>>     librdmacm: assuming: 4
>>     CMA: unable to get RDMA device list
>>     Hello world from processor dornroeschen.igpm.rwth-aachen.de
>>     <http://dornroeschen.igpm.rwth-aachen.de>, rank 0 out of 2 processors
>>     Hello world from processor dornroeschen.igpm.rwth-aachen.de
>>     <http://dornroeschen.igpm.rwth-aachen.de>, rank 1 out of 2 processors
>>     [dornroeschen.igpm.rwth-aachen.de:128141
>>     <http://dornroeschen.igpm.rwth-aachen.de:128141>] 1 more process
>>     has sent help message help-mpi-btl-base.txt / btl:no-nics
>>     [dornroeschen.igpm.rwth-aachen.de:128141
>>     <http://dornroeschen.igpm.rwth-aachen.de:128141>] Set MCA
>>     parameter "orte_base_help_aggregate" to 0 to see all help / error
>>     messages
>>
>>
> Thank you, Matthew, this solves my viewing problem. Am I doing 
> something wrong when initializing the matrices as well? The matrix' 
> viewing output starts with "Matrix Object: 1 MPI processes" and the 
> Krylov solver does not converge.
>
> Your help is really appreciated,
> Niklas Fischer
>>
>>
>> -- 
>> 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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