X grid is not uniform

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X grid is not uniform

Postby chinaye » Mon Jul 06, 2009 8:21 am

Dear Developers,
We do not know how to solve the error " [RL indx] X grid is not uniform. Gamma point only. " The ground-state calculation was carried out by using Abinit-5.7.2. Thank you very much.
Jianfei Ye, PHD
Shanghai Institute of Ceramic Chinese Academy of Science (SICCAS)
Email:jianfeiye@mail.sic.ac.cn
chinaye
 
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Re: X grid is not uniform

Postby andrea marini » Mon Jul 06, 2009 2:36 pm

chinaye wrote: We do not know how to solve the error " [RL indx] X grid is not uniform. Gamma point only. " The ground-state calculation was carried out by using Abinit-5.7.2. Thank you very much.


Dear Jianfei Ye,

we cannot help using the little information you provide. Please use the attachments to post

  • The input file (and pseudo files) of abinit
  • the input/report files generated by Yambo

Cheers
Andrea MARINI
Istituto di Struttura della Materia, CNR, (Italy)
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Re: X grid is not uniform

Postby chinaye » Tue Jul 07, 2009 6:55 am

andrea marini wrote:
Dear Jianfei Ye,

we cannot help using the little information you provide. Please use the attachments to post

  • The input file (and pseudo files) of abinit
  • the input/report files generated by Yambo

Cheers

Dear andrea marini,
The attachment, files. rar, includes the input files of abinit and files generated by Yambo. Thank you very much.
You do not have the required permissions to view the files attached to this post.
Jianfei Ye, PHD
Shanghai Institute of Ceramic Chinese Academy of Science (SICCAS)
Email:jianfeiye@mail.sic.ac.cn
chinaye
 
Posts: 16
Joined: Wed Mar 25, 2009 9:35 am

Re: X grid is not uniform

Postby myrta gruning » Fri Jul 10, 2009 6:49 pm

Dear Jianfei Ye,

the error you found it is due to the fact that Yambo needs a uniform grid. The grid generated by your abinit input is not uniform.
The shifts (shiftk and nshiftk input variables in ABINIT) have to be chosen properly in order to have a uniform grid. See http://www.abinit.org/documentation/helpfiles/for-v5.8/input_variables/varbas.html#shiftk.
Your choice
Code: Select all
nshiftk2 4
shiftk2  0.5 0.5 0.5  # These shifts will be the same for all grids
         0.5 0.0 0.0 
         0.0 0.5 0.0
         0.0 0.0 0.5

is fine just for an FCC but it produces a non uniform grid in your case.
By running with
Code: Select all
nshiftk2 1
shiftk2  0.0 0.0 0.0 #NO SHIFT

or
Code: Select all
nshiftk2 1
shiftk2  0.0 0.0 0.5 #

I avoided the problem you met.
Note that also the default shiftk (the one that is chosen if you not specify shiftk in your input), 0.5 0.5 0.5, will generate a non uniform grid!!!

I do not know if there are still other shiftk's that give a uniform grid that may be "better" from a numerical point of view, but with the two here you should be able to run your job.

Cheers,
m
Dr Myrta GrĂ¼ning
Atomistic Simulation Centre
Queen's University Belfast - Northern Ireland

http://www.researcherid.com/rid/B-1515-2009
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Re: X grid is not uniform

Postby chinaye » Mon Jul 13, 2009 12:49 am

Dear Myrta GrĂ¼ning,
thank you very much. Your answer helps me a lot.
Jianfei Ye, PHD
Shanghai Institute of Ceramic Chinese Academy of Science (SICCAS)
Email:jianfeiye@mail.sic.ac.cn
chinaye
 
Posts: 16
Joined: Wed Mar 25, 2009 9:35 am


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