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Subject: Re: [OMPI users] Two Instances of Same Process Rather Than Two SeparateProcesses
From: Gus Correa (gus_at_[hidden])
Date: 2011-03-08 10:53:24

Jeff Squyres (jsquyres) wrote:
> This usually indicates a mismatch of MPI installations - eg, you compiled against one MPI installation but then accidentally used the mpirun from a different MPI installation.
> Sent from my phone. No type good.
> On Mar 8, 2011, at 4:36 AM, "Clark Britan" <c.britan.j2_at_[hidden]> wrote:
>> I just installed OpenMPI on my Linux Ubuntu 10.04 LTS 64 bit computer. I
>> downloaded the most recent version of OpenMPI and ran the configure and make
>> commands.
>> I then tried to run a CFD software called FDS using 2 of the 12 available
>> processors (single node) as a test. I split my computational domain into two
>> meshes, as explained in the FDS manual and would like to run each mesh on a
>> separate core.
>> When I run the command mpirun -np 2 fds5_mpi_linux_64 room_fire.fds I get
>> the following error:
>> Process 0 of 0 is running on comp1
>> Process 0 of 0 is running on comp1
>> Mesh 1 is assigned to Process 0
>> Error: MPI_PROCESS greater than total number of processes
>> Why are two instances of the same process run instead of two separate
>> processes? What I expect to see after running the above command is:
>> Process 0 of 1 is running on comp1
>> Process 1 of 1 is running on comp1
>> Mesh 1 is assigned to Process 0
>> Mesh 2 is assigned to Process 1
>> ...
>> Any idea what is going on? Thanks for the help.
>> Kind Regards,
>> Clark

Hi Clark

Any chances that MPI_PROCESS was not properly set in your FDS parameter
I am not familiar to the FDS software, but it looks like MPI_PROCESS is
part of the FDS setup, and the error message seems to complain
of a mismatch w.r.t. the number of processes (-np 2).
Maybe it takes a default value.

Also, if you just want to check your OpenMPI functionality, download
the OpenMPI source code, compile (with mpicc) and run (with mpirun)
the hello_c.c, connectivity_c.c, and ring_c.c programs in the 'examples'
directory. This will at least tell you if the problem is in OpenMPI or
in FDS.

My two cents,
Gus Correa