[gmx-users] time of simulation

2009-07-25 Thread mahmoud 
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!
 
 
Thank you very much for your kind help.
 
Best,
Mahmoud


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Re: [gmx-users] time of simulation

2009-07-25 Thread 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.
-- 
--
Jussi Lehtola, FM, Tohtorikoulutettava
Fysiikan laitos, Helsingin Yliopisto
jussi.leht...@helsinki.fi, p. 191 50632
--
Mr. Jussi Lehtola, M. Sc., Doctoral Student
Department of Physics, University of Helsinki, Finland
jussi.leht...@helsinki.fi
--

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