[Wien] lapw0_mpi for dual cores

[Peter Blaha]

Autoparallelization NEVER works reasonable (in my experience). Compilers 
are still very bad in this respect. One would have to identify the time 
consuming loops and put explicit parallelization statements into the code.

lapw0_mpi should reduce your time in lapw0 by about 40%.
For mpi: How did you "configure WIEN" (parallel options in siteconfig),
see also the file   $WIENROOT/parallel_options

Try to run lapw0_mpi "by hand". The exact command depends on your mpi, but 
something like that should work:

mpirun -np 2 -hostfile machines lapw0_mpi lapw0.def

The file "machines" should contain two lines with the names of your dual 
core pc.

On some mpi versions you need -machinefiles instead of -hostfile;
or mpirun is called mpirun_ssh or similar.

Check your mpi:   
which mpirun
man mpirun
or mpirun -h  (or --help),....


> I've tried to compile using mpi (intels version) now. Seems to compile
> fine, but I'm not able to run it. in my machines file I added lapw0:pc:2
> 
> in the mpd.hosts file I added 
> pc
> pc
> 
> If anyone has any experience with this it would be great
> 
> Michael 
> 
> On Sat, 2006-09-09 at 09:05 +0200, Michael Gurnett wrote:
> > Tried that now, and the reulst is that with -parallel there is a 20
> > second speed increase for a 44 min lapw0 run. So I would say the
> > increase is quite insignificant. Still it was worth a try.
> > 
> > Michael
> > 
> > 
> > On Fri, 2006-09-08 at 19:23 +0200, Gerhard H Fecher wrote:
> > > Did you try to compile simply with the auto paralelliser:  -parallel 
> > > 
> > > I did not check it up to know but would be interesting if it speeds up on dual 
> > > core machines without using special mpi libraries, what would be easier for 
> > > unexperienced users.
> > > 
> > > Ciao
> > > Gerhard
> > > 
> > > Am Freitag, 8. September 2006 18:29 schrieb Michael Gurnett:
> > > > I've been checking the system monitor and it appears that even with
> > > > OMP_NUM_THREADS=2 lapw0 really only using about 50% of the processing
> > > > power of the dual cores. Has anyone tried using lapw0_mpi for a dual
> > > > core, and was it easy to implement
> > > > 
> > > > 
> > > > Thanks 
> > > > 
> > > > Michael
> > > > 
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                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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