[Pw_forum] band and dos input files in xcrysden

[Eduardo Ariel Menendez Proupin]

Dear Tone,
Thanks for your interest in my request.

>Don't know what exactly you mean for Emin and Emax, however, as far as
>the outdir and prefix are concerned, how should pwgui know which is the
>corresponding pw.x input file? (this would be needed for the
>inheritance).

Let me remind how is the process to obtain the DOS. It has three
calculations and 3 input files

pw.x < si.scf.in > si.scf.out   # self consistent
pw.x <si.dos.in > si.dos.out  # non selfconsistent dense k-points mesh and a
few options
dos.x <si.dos2.in >  si.dos2.out  # postprocessing


At present, pwgui has a Menu File/New, where one can define the input files
from the scratch.

A typical input for dos.x looks like this
&inputpp
     outdir='./temp',
     prefix='silicon'
     fildos='silicon.dos',
     Emin=-10.0, Emax=25.0, DeltaE=0.1
/
One simple idea is to add a submenu to the menu  "File/New from here"
So, if I have an open pw.x input, when I select "File/New from here" it will
make the new file inheriting all the properties: in this case outdir and
prefix. I would also set by default fildos = prefix.dos.

Emin and Emax are the minumum and maxima of the Kohn-Sham eigenvalues that
can be taken from the pw.x outputs. pwgui may run an script to take these
values from the pw.x output if this exists (I may want to run the files
interactvely or just to make the input files and copy them to a server). We
may ask Paolo  to put Emin and Emax, and Efermi or HOMO in a single line of
the output.

NSCF calculation inherits many more fields from the SCF, so it makes more
sense to generate the *.dos.in file from the .scf.in file. Let see the
differences

diff si.scf.in si.dos.in
2c2
<                  calculation = 'scf' ,
---
>                  calculation = 'nscf' ,
15a16,17
>                         nbnd = 8,
>             occupations='tetrahedra',
29c31
<   5 5 5   1 1 1
---
>   20 20 20   0 0 0

This I make simply saving the si.scf.in with the name si.dos.in and changing
the variables. However, it may be nice to make the changes automatically.
The keywords nbnd, occupations, and the k-point mesh (20 20 20) are
difficult to set automagically. I propose some maybe good default values

nbnd can be searched in the output file.

grep 'number of Kohn-Sham states' si.scf.out
     number of Kohn-Sham states=            4
and just double the number 4. It would be a different recipe if we deal with
a  metal, but let's keep simple and let the user to reduce it.

I would set occupations='tetrahedra' by default.

>   20 20 20   0 0 0
I would make a contest to select the winning idea. I have one recipe
If I have in the scf input calculation
K_POINTS automatic
N1 N2 N3 1 1 1  or 'N1 N2 N3 0 0 0'
then for the nscf calculation I would set
N1n N2n N3n 0 0 0

such that
N1n/N1 = N2n/N2 = N3n/N3 and
N1n*N2n*N3n = (30^3)/nat   (nat the number of atoms)

A different strategy may be to have a menu Project and from the Project
menu, select kinds of input fiiles or tasks. If one selects task  DOS, for
example, then pwgui can  create the three input files and display a reminder
of the sequence of calculations to be done.


Best regards
Eduardo


> ---------- Mensaje reenviado ----------
> From: Tone Kokalj <tone.kokalj at ijs.si>
> To: PWSCF Forum <pw_forum at pwscf.org>
> Date: Fri, 20 Feb 2009 12:08:43 +0100
> Subject: Re: [Pw_forum] band and dos input files in xcrysden
> On Thu, 2009-02-19 at 23:48 -0300, Eduardo Ariel Menendez Proupin wrote:
> > Hi Tone,
> >
> > Do you have plans to add the capability in PWGUI to generate inputs
> > for bands.x and dos.x ?
>
> Actually, I didn't have, but this can be easily done. Due to your
> request I will do so in the future.
>
> > It would be goood to operate it in an easy way, i.e. inheriting
> > outdir and prefix from the parent pw.x input and Emin=-10.0, Emax=25.0
> > from the pw.x output.
>
> Don't know what exactly you mean for Emin and Emax, however, as far as
> the outdir and prefix are concerned, how should pwgui know which is the
> corresponding pw.x input file? (this would be needed for the
> inheritance).
>
> Regards, Tone
>
>
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