[Pw_forum] parallel execution of PWscf

[Lorenzo Paulatto]

In data 24 luglio 2009 alle ore 13:36:10, Neel Singh  
<neelphysics at yahoo.in> ha scritto:
> I am using LG Quad core processor machine with PWscf running on linux. I  
> want to know whether there is any command to run it parallely on the  
> four processors or by default with simple installation (i.e.,   
> ./configure and make all) it uses all the four processors?

Dear Neel,
QE uses mpi for parallelization. Which means, you have to compile it with  
mpi libraries in order to produce a parallel executable. If the configure  
script can detect any mpi implementation (such as the popular opnmpi) it  
will use them, and print this message:
   Parallel environment detected successfully.
   Configured for compilation of parallel executables.
How to run a code parallelized with mpi depends on its implementation,  
usually something like
   mpirun -np 4 pw.x ...
is required.

Very recently openmp (which is totally different from mpi/openmpi) has  
also been implemented in QE. Although it is  still experimental it does  
not require any specific library (but a openmp-capable compiler) and may  
be more appropriate for a multi-core single-node configuration.

best regards

-- 
Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
skype: paulatz
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