[gmx-users] time of simulation

[Jussi Lehtola]

On Sat, 2009-07-25 at 15:16 -0700, mahmoud wrote:
> Hello Dear GMX Users,
>  
>  
> I have installed Gromacs 4 on a QUAD computer by Fedora 11.
>  
> When I do not use the "mpirun -np 4 g_mdrun ... " command, just one
> CPU is used.
> When I use the "mpirun -np 4 g_mdrun ... " command, all of the 4
> CPUs are used.
>  
> But the problem is that the time of simulation, although 4 CPUs are
> used, does not change by using the mpirun command!
> 
> Can you help me please how I can fasten the time of simulation!

If you are using the Fedora RPMs, you need to run
$ mpirun -np 4 g_mdrun_mpi
instead of
$ mpirun -np 4 g_mdrun
as the latter will just get you four independent processes that all
perform the same calculation.
-- 
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Jussi Lehtola, FM, Tohtorikoulutettava
Fysiikan laitos, Helsingin Yliopisto
jussi.lehtola at helsinki.fi, p. 191 50632
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Mr. Jussi Lehtola, M. Sc., Doctoral Student
Department of Physics, University of Helsinki, Finland
jussi.lehtola at helsinki.fi
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