[Pw_forum] HI

Gabriele Sclauzero sclauzer at sissa.it
Tue Nov 10 10:03:10 CET 2009

Dear Mohsen,

   first of all, in this forum we encourage people to sign their mails and put their 
affiliation. We will be grateful to you!

   Inspecting your input file, I saw plenty of pw input keywords that I didn't even know 
that actually existed... seriously: one good thing of using namelists for input is that 
you need to specify only the parameters that you need to change. For the others the 
default is usually good, or at least it is better not to change them unless you know 
exactly what you are doing.

   On the other hand some parameters need to be changed (to check for numerical accuracy, 
for instance). Two of these are the plane waves cutoff of the wavefunctions and the charge 
density. In your file I found:

                      ecutwfc = 5 ,
                      ecutrho = 5 ,

Which are very low values and moreover not compatible. ecutrho must be at least 4*ecutwfc 
  (this is the default and it is fine for normconserving PPs, while for ultrasoft you may 
need much higher ratio ecutrho/ecutwfc, which is also called "dual")



mohsen modaresi wrote:
> Hi
> I faced with a problem.
> I made a file with "pwgui" but when i run "pw.x" i faced with this message
>               from iosys : error #         1
>                  invalid dual?
> What it means?
> And i send that file.
> With especial thanks.
> ------------------------------------------------------------------------
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> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum


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