[DFTB-Plus-User] opinions about atomic cluster input file

[Bálint Aradi]

> 
> i try to calculate ground state energy of Boron atoms by using DFTB+,
> i used the parameter in input file which is randomly refer from
> difference reasonable input file sources,
> the problem is, when i calculate small ( < 6 ) number of the atomic
> cluster, the result obtained in a short time (  2-3 minutes ),
> but, when i calculate for bigger ( > 10 ) number of atomic cluster, the
> time taken to obtain result is much more longer ( 1-3 hours ),

 Diagonalization usually scales as N^3, so, if you have 2 times more
atoms, you wait 8 times longer. Also, depending on the size of your
system, the number of conjugate gradient optimization steps could easily
increase with increasing number of atoms. Finally, your problem could be
also I/O related, as you are writing autotest.tag in every iterations.
Turning this off may also speed up your calculation.

  Best regards,

  Bálint



-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b_aradi/


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