[Wien] optimization/minimization

[Jeff Spirko]

Travis,

If you just run min_lapw with no options, the default job sets force
convergence, so there should be no problem.  (Run "min_lapw -h" to
see the default job.)

If you set your own job with 'min_lapw -j "runsp_lapw ..."', it is
important during a minimization that the full forces be calculated.
This requires FOR to be set at the beginning of case.in2[c] for at
least the last iteration.  To get this, there are several options:

1.  Set FOR yourself for the entire cycle.  This will make the
    calculation take longer in the lapw2 step, but you can just use
    -ec.
2.  Run to energy convergence with TOT set in case.in2[c], set FOR,
    then run one more iteration.  One way of doing this is to set
    your job in minimization to "runsp -I -ec x ; runsp -fc y".
3.  Use -fc.  This automatically sets FOR for the last iteration
    only.

Best Regards,
-Jeff Spirko

On Tue, Feb 22, 2005 at 09:39:02AM -0500, Travis Sefzik wrote:
> Hello WIEN users,
> 
> I was wondering if anybody could confirm that the below steps are 
> performing the tasks that I desire.
> 
> 
> If I would like to perform a force minimization:
> 
> 	init
> 	run -fc x   (where x is where I am telling WIEN to converge)
> 		-- now inspect
> 	min
> 
> the above should provide me with an optimized structure via force 
> minimization
> 
> 
> Alternatively, energy minimization could be achieved as such:
> 
> 	init
> 	run -ec x   (where x is where I am telling WIEN to converge)
> 		-- now inspect
> 	min
> 	
> 
> This question has been presented mainly to ask if the energy 
> minimization through energy convergence follows the same procedure (as 
> I have become accustomed to thinking about minimization with respect to 
> energy, not force minimization thus far).  If this is correct that I 
> can go about minimization with energy convergence, has anybody noticed 
> any drawbacks to using this approach?
> 
> Thank you,
> Travis
> 
> 
> 
> 
> 
> ---
> Travis Sefzik
> Grandinetti Group
> Chemistry Department
> The Ohio State University
> 100 W. 18th Ave.
> Columbus, OH 43210
> 
> phone: (614) 292-8064
> fax: (614) 292-0559
> email: tsefzik at chemistry.ohio-state.edu
> 
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-- 
Jeff Spirko   spirko at lehigh.edu   spirko at yahoo.com   WD3V   |=>

The study of non-linear physics is like the study of non-elephant biology.

All theoretical chemistry is really physics;
and all theoretical chemists know it. -- Richard P. Feynman