[Pw_forum] k point parallel

[Axel Kohlmeyer]

Jian ZHOU wrote:
> Dear all

dear jian,

> 
> It is said in the manual that pwscf can be paralleled by "k points 
> parallelization" or by " PW parallelization". Since in our Gigabit 
> ethernet, the parallelization performances is not so good, so, is it 
> possible for pwscf to parallel only on the k points, not on the PW? 

yes. please have a look at the manual. you need to give the additional
flag -npool to the executables. this decides, how many k-point pools
will be used. note that this should be a divisor of the number of cpus
requested and the number of k-points. for optimal performance, you
also need a _local_ scratch area on each node (and specify that
in your input) and set the keyword wf_collect=.true. so that the
final restart is collected to a shared directory, or else you would
most likely not be able to restart or continue with the next job, as
you would need to have the exact same nodes in the exact same order
assigned for that job.

there are more details about this in the manual and Doc/INPUT_PW.
this also has been discussed before, so have a look at the mailing
list archives as well (you can even (ab-)use google for that, by adding
site:www.democritos.it to your search).

regards,
      axel.


> 
> Thank you.
> 
> Best wishes,
> 
> Jian
> 
> 


-- 
=======================================================================
Axel Kohlmeyer    e-mail: akohlmey at cmm.upenn.edu, tel: ++1-215-898-1582
    Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.