[gmx-users] Using -multidir option on Cray (aprun)

[Suman Chakrabarty]

Dear all,

I have managed to resolve this issue, which was a shell scripting mistake.
My mistake was to keep "-multidir remd_{1..2}" inside quotes, hence the
Bash expansion of remd_{1..2} did not work as intended. Instead, "-multidir
$(echo remd_{1..2})" works. But if anybody has any better suggestion,
please let me know. Thanks.

Regards,
Suman.

On Wed, Sep 11, 2019 at 12:04 PM Suman Chakrabarty <
chakrabarty.suman at gmail.com> wrote:

> Hello!
>
> I am trying to use the -multidir feature of mdrun for setting up a REMD
> simulation on a Cray XT system. It requires the "aprun" launcher to spawn
> the parallel processes rather than the usual mpirun (which I have
> successfully used with -multidir before).
>
> I am using the 2019.3 version of Gromacs and I can successfully run normal
> parallel Gromacs jobs (without -multidir) in this system.
>
> I have the following setup in my submission script:
>
> exec1="/home/chs1/soft/GMX2019.3/bin/mdrun_mpi -ntomp 1 -deffnm nvt
> -multidir remd_{1..2}"
>
> aprun -n 64 -N32 -d1 ${exec1}
>
>
> I get the following error message from all 64 MPI processes:
>
> MPI rank:    8 (out of 64)
>
> Source file: src/gromacs/mdrun/multisim.cpp (line 77)
>
> To run mdrun in multiple simulation mode, more then one actual simulation
> is required. The single simulation case is not supported.
>
> I don't understand why Gromacs is treating this as "single simulation
> case"! Can anybody with more experience in using the -multidir option in a
> Cray system suggest any solution to this problem? Thanks.
>
>
> Regards,
>
> Suman.
>
>
>