[Pw_forum] How to integrate a particular PDOS column

[Gabriele Sclauzero]

On 07/23/2010 08:37 AM, Haruhiko Dekura wrote:
> Dear Nand
>
> You can integrate each PDOS files to obtain the total PDOS for 
> selecting orbitals by using sumpdos.x.
>
> Below is the output of help message from sumpdos.x;
>
> ./sumpdos.x -h
> ----------------------------------------
> USAGE: sumpdos [-h] [-f <filein>] [<file1> ... <fileN>]
>   Sum the pdos from the file specified in input and write the sum
>   to stdout
>      -h           : write this manual
>      -f <filein>  : takes the list of pdos files from <filein>
>                     (one per line) instead of command line
> <fileM>      : the M-th pdos file
> ---------------------------------------------
>
> And see also user-guide.

This utility is meant for summing the PDOS from several files 
(corresponding to different atoms) in order to get a single PDOS, but 
does not compute any integral of the PDOS, so I don't think that's what 
Nand needs.

>
>
>
> Hope this helps.
> Haruhiko Dekura
>
>
>
> On 2010/07/23, at 14:47, nand wrote:
>
>> Dear      Dr Sclauzero and PW users,
>> Thanks for replying on my last query. Now i would like to know (as a 
>> new user) how to integrate a particular column of PDOS file . Is 
>> there a tool for that or is done using ones own program.

I think there's no such utility in the QE package, but if the energy 
grid is dense enough you can use the very simple rectangle method 
(that's what is used in PP/dos.f90 for integrating the DOS, for instance).
You can test the accuracy by looking how the integral converges when the 
energy step is reduced, obviously (should be O(deltae^2) ).
If you want something more precise you may need to refer to some 
numerical analysis textbook or to the old good Numerical Recipes, that 
used to be available online, for instance.

GS

>> Thanking you in advance.
>>
>> Nand Rana
>> Ranchi University.
>> India
>>
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-- 

Gabriele Sclauzero, EPFL SB ITP CSEA
PH H2 462, Station 3, CH-1015 Lausanne

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