[mpich-discuss] coupling

[Gus Correa]

Hi Fereshteh

1) I would look for log or error messages in the model
output *before* the final one ("MPI_Abort ...").

Although it aborted with 2 processors,
that was a graceful termination by the program.
So what is before the last error message may shed some light
on why the model aborted,
and what it requires to run correctly.

**

2) MCT is also used for coupling climate models that we use
here.  Some  of these models it run in SPMD mode (i.e. a single
executable is launched by mpiexec).
Others run in MPMD mode (i.e. several executables
are launched by mpiexec, which requires a mpiexec command
line with more parameters).

Your mpiexec suggests that the model relies on a
single executable (oceanG).
However, this may/may not be the case, as you mentioned
three separate items also: ROMS, SWAN, and the coupler.

Is it a single executable or more than one that your model
uses?
[If you describe how you compile the model it may help.]

**

3) Are you trying to run it in hybrid mode, i.e.
using both MPI and OpenMP?

I am not familiar to this model,
so I am just guessing.

The conventional wisdom is to use parameters names like
"Nthreads" for OpenMP threads, although parameter names are elusive.
OpenMP would add another twist to your processor configuration,
as you would need to provision additional processors
for OpenMP, besides those for MPI.

**

4) Does the domain decomposition (Ntilei and Ntilej) have to
be the same for both models?


Have you tried something like:
Ntilei=2
Ntilej=2
i.e. 2*2=4 processors for the ocean
plus one processor for SWANN, a total of 5 processors,
then:

mpiexec -np 5 ...

In some models we run here (e.g. MITgcm) you need to match precisely
the number of processors to the tiles used to decompose your domain
(and possibly also the OpenMP threads).

When you tried mpiexec -np 2, did you choose Ntilei=Ntilej=Nthreads=1 
for both models?

Do you have perhaps to add one processor (or more)
specifically for the coupler?

**

5) Do your input files (describing the ocean initial state,
and perhaps the wave state), have to be organized based on the
"tile" configuration, or can they span the whole domain?
This could be another source of error.

6) Does ROMS and SWANN have mailing lists that can perhaps help
you more than the generic MPICH list?


I hope this helps,
Gus Correa


On 10/27/2013 06:33 AM, fereshteh komijani wrote:
>   Sure.
>
>   ROMS and SWAN models are models for ocean and wave models,
> respectively.  Coupling of them require 3 input files: coupling_test.in
> <http://coupling_test.in>, swan_test.in <http://swan_test.in> and
> roms_test.in <http://roms_test.in> which first one is coupled input file
> and also one build.bash file  which in it user called requested
> libraries, cpp optins, header file, compilers (for me gcc and gfortran).
>   For example in build.bash file I set
>
> USE_MPI=on = on
> USE_MPIF90 =on
>
> WHICH_MPI=mpich2
>
> FORT = gfortran
>
> also with regard that for coupling model, MCT (model coupling toolkit)
> is necessary I have installed it and set its  include and lib
> directories in build.bash file.
>
> In coupling_test.in <http://coupling_test.in> user call swan_test.in
> <http://swan_test.in>and roms_test.in <http://roms_test.in> as wave and
> ocean model's inputs.
>
> In roms_test.in <http://roms_test.in> some coefficients, solving
> technique and some input forcing file determined.
>
> for choosing number of nodes for each model there are NtileI and Ntilej
> in roms_test.in <http://roms_test.in> and Nthreads (ocean) and Nthreads
> (wave) in coupling_test.in <http://coupling_test.in> file ( Nthreads
> (ocean)=NtileI *Ntilej ) and total nodes are equal to Nthreads
> (ocean)+Nthreads (wave).
>
> whenever i set one  node for wave model (SWAN) (Nthreads (wave)=1) after
> running by
>
> mpirun -np 2 ./oceanG coupling_inlet-test.in
> <http://coupling_inlet-test.in/>>mpi.log
>
> it replies:
>
> application called MPI_Abort(comm=0x84000002, 4) - process 0
>
> But when setNthreads (wave)>1 (and everything for Nthreads (ocean)) for
> example
>
> mpirun -np 8 ./oceanG coupling_inlet-test.in
> <http://coupling_inlet-test.in/>>mpi.log
>
> mpi.log file (attaché file) shows that roms model does not have problems
> and its nodes are active but nothing happen for swan model after 2 weeks
> than running.
>
> I hope that this information be sufficient.
>
> All the best
>
> fereshte
>
>
>
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