[Pw_forum] How to parallelize phonons

[Paolo Giannozzi]

On Mar 28, 2012, at 20:34 , Alejandro Rébola wrote:

> Where could I find more documentation about this

there is something in the user guide. The reference paper is  
unfortunately
published in an exotic place:
{\it Calculation of Phonon Dispersions on the GRID using Quantum  
ESPRESSO},
      R. di Meo, A. Dal Corso, P. Giannozzi, and S. Cozzini, in
      {\it Chemistry and Material Science Applications on Grid  
Infrastructures},
      editors: S. Cozzini, A. Lagan\`a, ICTP Lecture Notes Series,
      Vol. 24, pp.165-183 (2009).
You can parallelize over images (irreps and wavevectors) manually  
(i.e. splitting
the complete phonon calculation into smaller pieces, sending them to  
many
different machines, or many different jobs); or automatically, using  
MPI (in a
single run). The latter approach allows running on a large number of  
processors
(something that makes people in large computer facilities happy) but  
the load
balancing is less than ideal, to say the least. A better strategy  
likely is to write
a simple "dynamical" scheduler that submits images when groups of  
processors
are ready, but this requires some work.

> or some example?

for "manual" parallelization, see examples/GRID_example

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222