[gmx-users] Re: Gromacs and mpirun

[David van der Spoel]

Lam Nguyen Sy wrote:
> Dear Gromacs users,
> 
> I'm trying to run Gromacs version 3.3.1 in parallel.
> The following are what I did and what I encountered:
> 
> ${direxe1}/mpirun  -np ${ncpu} ${direxe}/mdrun_d_mpi 
> -np ${ncpu} -s ${type2}.tpr  -e ${type2}.edr -o
> ${type2}.trr -g ${type2}.log -c ${type2}.gro
> 
> Fatal error:
> run input file md961.tpr was made for 2 nodes,
> while mdrun_d_mpi expected it to be for 1 nodes.
> 
> Here,
> ncpu=2
> direxe1=/MPI/nslam/mpich-1.2.7p1/bin
> direxe=/MPI/nslam/GR/bin
> Certainly, I did grompp_d_mpi before mdrun_d_mpi.
> 
> And the below is the whole story.
> 
> I used to run Gromacs in parallel without any
> difficulty on a Beowulf cluster. I did like this:
> 
> mpd &
> mpirun ... mdrun_d_mpi
> 
> But, everything has changed since the administrator of
> the cluster upgraded the system from python2.3 to
> python2.4. I cannot use "mpd" anymore,
> 
> mpd &
> /usr/bin/env: python2.3: No such file or directory
> 
> Instead, I did the following way and Gromacs could run
> in parallel:
> 
> python2.4 {path_to_Mpich}/bin/mpd &
> python2.4 mpirun ...mdrun_d_mpi
> 
> I had to put "python2.4" before any command related to
> mpi (I don't know why). But, a very strange thing
> happened. With the preceeding python2.4, Gromacs could
> run in parallel within 70 minutes with 100% and 92% of
> each processor (before, they were just 99% each), then
> it broke with these lines:
> 
> mpiexec_bw4: cannot connect to local mpd
> (/tmp/mpd2.console_nslam); possible causes:
> 1. no mpd is running on this host
> 2. an mpd is running but was started without a
> "console" (-n option)
> 
> and there was no mpd anymore.
> 
> Then, I tried to reinstall fftw-3.1.2 and
> gromacs-3.3.1 in the following way (I thought that
> gromacs did recognize something new on the system):
> 
> fftw-3.1.2
> 
> ./configure --enable-double
> --prefix=/MPI/nslam/fftw-3.1.2
> 
> gromacs-3.3.1
> 
> export CPPFLAGS=-I/MPI/nslam/fftw-3.1.2/include/
> export LDFLAGS=-L/MPI/nslam/fftw-3.1.2/lib/
> ./configure --enable-double --enable-mpi
> --program-suffix='_d_mpi' --prefix=/MPI/nslam/GR/
> 
> These are what I did long time ago, and Gromacs had
> been working very properly till the time of upgrading.
> 
> The suceeding "make" and "make install" of those
> packages gave no complain (certainly, I did "make
> distclean" before recompiling). But, the situation was
> exactly the same as what before I reinstalled them.
> With the preceeding "python2.4", Gromacs could run
> with 100% and 92% cpu within just about 70 minutes,
> then broke with no mpd. 
>  
> I thought the problem wasn't of gromacs-3.3.1, but the
> mpi on the system. Unfortunately, the administrator of
> the system didn't want to think that it was the
> problem of the mpi he did install. Therefore, I tried
> to install mpi myself. I did:
> 
> ./configure --with-arch=LINUX --with-device=ch_p4
> -rsh=/usr/bin/ssh --prefix=/MPI/nslam/mpich-1.2.7p1
>   
> After that, I did "make distclean" in both fftw and
> gromacs and recompiled them the same way as above,
> with:
> 
> export MPI=/MPI/nslam/mpich-1.2.7p1/bin
> export MPICHHOME=/MPI/nslam/mpich-1.2.7p1/bin
> 
> Then what I did and received are what was said at the
> beginning of this message. Besides, it was ok when I
> did that way with ncpu=1.
> 
> Now I don't know what is the problem, of mpi or of
> Gromacs for parallel running? 
> 
> I'm not sure that my story and my questions are posed
> on the appropriate mailing list. Forgive me if it was
> not the case.
> 
> Is there any idea on my problem? If there is, it will
> be very useful for me.
> 
> Thank you very much,
> 
> And have a nice weekend
> 
> nslam
> 
There have been many reports of problems with MPICH. I would complain to 
the system administrator, but a quick workaround would be to install LAM 
or OPENMPI in your homedirectory and link gromacs to that.



-- 
David van der Spoel, Ph.D.
Molec. Biophys. group, Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205. Fax: +4618511755.
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se