[Pw_forum] Choice of irreducible representations with ph.x

Cristian Degli Esposti Boschi cristian.degliesposti at unibo.it
Tue Mar 31 14:57:11 CEST 2009


I would like to perform a phonon calculation
at Gamma making a choice of only a selected number
of irreducible representations. After a proper scf
calculation I use with ph.x with an input file
like the following one:

Phononic spectrum (1) of CoM (at Gamma)
  &inputph
  amass(1)=1.00794,
  amass(2)=12.011,
  amass(3)=14.007,
  amass(4)=15.999,
  amass(5)=55.845,
  prefix='CoM',
  outdir='/scratch/userinfm/cne0fm4a/CoM/results/',
  iverbosity=1,
  epsil=.false.,
  fildyn='CoM.dm',
  nrapp=1,
  /
  0.0 0.0 0.0
  1


The problem is that the calculation seems to proceed ignoring
the nrapp value and the list of numbers I put in the last line
and all the irreps are considered. This happens both for nrapp=1
(one value in the list) or nrapp>1 (nrapp values in the list).
pw.x and ph.x are run on the CINECA cluster where there appears to be QE 
ver. 4.1CVS and I would liketo save cpu time by excluding the undesired 
irreps.

Using the same syntax (nrapp and the list of irreps at the end)
to modify the scripts of example02 I successfully select only one of the 
two irreps for Si with QE ver. 3.2 installed on a desktop pc (reporting 
the message "Not done in this run"). Might it be a version issue?

Thanks a lot for your help and time.
-- 
___________________________________________________
Cristian Degli Esposti Boschi
CNR, CNISM, Unita' di Ricerca di Bologna, c/o
Dipartimento di Fisica, Universita' di Bologna
viale Berti-Pichat, 6/2, 40127, Bologna, Italia
tel. ++39 051 2095114   fax ++39 051 2095113
e-mail: cristian.degliesposti -AT- unibo.it
web:    http://www.df.unibo.it/fismat/theory
___________________________________________________




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