[Q-e-developers] EXX and band-groups: exxbuff

[Andrea Ferretti]

Dear all,

I'm writing regarding the band-group parallelism of the EXX part of pw.

I've noticed that the workspace exxbuff in exx.f90 is allocated as
(npw, nbnd, nqs ) independently on the number of band groups used...

In order to reduce the allocated memory (when nbgrp > 1 ) I've ported to bgrp 
parallelism to all routines in exx.f90 and resized the allocation of exx
(everything seems to work now, including stress and restart).

nevertheless, before commiting I would like to enquire people that have been 
working extensively on the exx part about these changes...
do you foresee any related problems ?
any reasons not to do that ?

last but not least:
it seems to me that, even with disk_io = "high", the restart_exx files are not 
automatically written unless a clear exit is invocated..
Shouldn't the default be that restart files for exx are written after every exx 
iteration is completed (at least with disk_io = 'high') ??

thanks
Andrea


-- 
Andrea Ferretti
S3 Center, Istituto Nanoscienze, CNR
via Campi 213/A, 41125, Modena, Italy
Tel: +39 059 2055322;  Skype: andrea_ferretti
URL: http://www.nano.cnr.it