[Pw_forum] dos.x and wave function files

[Giovanni Cantele]

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