[Pw_forum] dos.x and wave function files

[Paolo Giannozzi]

If I remember correctly, "read_xml_file" does not read the wavefunctions.

Paolo

On Mon, Jun 27, 2016 at 3:48 PM, Giovanni Cantele
<giovanni.cantele at spin.cnr.it> wrote:
> Dear all,
>
> I’ve a simple question concerning the calculation of density of states with ngauss=0 using dos.x.
> The point is that this DOS calculation does not require the knowledge of the wave functions, because just a weighted sum on eigenvalues is computed:
> dosg (ns) = 0.0d0
>      DO ik = nk0, nk0 + nk-1
>         DO n = 1, nbnd
>            dosg (ns) = dosg (ns) + wk (ik) * w0gauss ( (E-et (n, ik) ) &
>                 / Degauss, ngauss)
>         ENDDO
>      ENDDO
>
> However, if using a fine k-point grid on a large system, it might happen that to speed up the calculation the use of pools is required, in the nscf calculation of pw.x,
> with wf_collect = .true. (to avoid incompatibility with dos.x). This can mean a very large occupation of disk space on the master node, for storing wave functions
> that are not actually required.
>
> The question is: to prevent the code from writing the eigenvalues and not wave functions and make dos.x working even in the absence of wave functions, I can set
> disk_io = ‘none’ in the pw.x input. But then, is there a simple way (e.g. commenting selected lines in the code) to prevent the dos.x call to read_xml_file from
> reading wave functions from files?
>
> Of course I know that I can just let pw.x print the eigenvalues and calculate DOS by myself, but I wonder if there is a simple workaround to let pw.x/dos.x
> do the calculation without explicit need of wave functions.
>
> Thanks.
>
> Giovanni
>
>
> --
>
> Giovanni Cantele, PhD
> CNR-SPIN
> c/o Dipartimento di Fisica
> Universita' di Napoli "Federico II"
> Complesso Universitario M. S. Angelo - Ed. 6
> Via Cintia, I-80126, Napoli, Italy
> e-mail: giovanni.cantele at spin.cnr.it
> Phone: +39 081 676910
> Skype contact: giocan74
>
> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
> Web page: http://people.na.infn.it/~cantele
>
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum



-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222