[Pw_forum] optimizing pw input parameters
meisam_a84 at yahoo.com
Mon Dec 24 12:15:54 CET 2007
Dear Osman Baris
I'm working on zigzag carbon nanotube. my problem is that my system doesn't converg , I don't know the steps in order that the parameters should be optimized. I don't know the mixing beta should be optimized or not! I have to mention that there is overlap in Davidson diagonalization.
Physics Department of Kashan university.
----- Original Message ----
From: "mbaris at metu.edu.tr" <mbaris at metu.edu.tr>
To: PWSCF Forum <pw_forum at pwscf.org>
Sent: Sunday, December 23, 2007 3:20:24 PM
Subject: Re: [Pw_forum] optimizing pw input parameters
Dear Meisam Aghtar,
> which parameters should be optimized sequencly in a scf runing? the
> parameters are celldm(1),ecutwfc, ecutrho,mixing-beta and K-points.
All of them.
> another problem is that for optimizing the ecutwfc the system
> converges for some numbers and it doesn't for some more. I have to
> mention that there is overlap in davidson diagonalization.
yes, they have such bad manners.
As previously mentioned in the forum, observables such as celldm(1)
converge much more rapidly than total energy. I do not know about your
specific problem, but what I do for in the project I am currently
working on is this: I have written a small script that scans a given
parameter range (ecutwfc, ecutrho, etc) and minimizes celldm(1) for the
specific set using a golden search algorithm, then, plotting the
results (for example celldm(1) vs ecutwfc for different k-point sets),
I decide which set to use.
why do you want to alter mixing beta? Do you have convergence problems?
and for ecutrho, it is generally safe to use 10xecutwfc, (remember, I
do not know what you are working on, and assuming something
straightforward). Please dig more about how ecutrho is used in the
code. and it is better to add your affiliation after a post.
Merry X-mas everyone!
Osman Baris Malcioglu
Pw_forum mailing list
Pw_forum at pwscf.org
Looking for last minute shopping deals?
Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the users