[Wien] Minimization: acceptable approximations

[L. D. Marks]

I'm running some fairly large surface minimizations, and simultaneously
looking for any tweaks that can be used in the port minimizer to improve
its performance. For a large minimization one obviously wants to reduce
the accuracy of the calculation (for speed) -- then step it up close to
the minimum. What I'm currently using is:

	1) Small number of k-points (TETRA mode)
	2) Small RKMAX (6)
	3) .fulldiag (the extra CPU time is minimal with mkl6.1)
	4) -fc 1.0 (larger seems to be too inconsistent)

I'd be interested in any comments about other possible tricks to use, and
user experience. I'd also appreciate input about CPU-effective ideas about
improving the accuracy of the force calculation (R0 ?), and what
parameters effect this. (It looks to me like in some cases the forces
could be slightly inconsistent with the energy.)

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Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2225 N Campus Drive
Northwestern University
Evanston, IL 60201, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
mailto:L-marks at northwestern.edu
http://www.numis.northwestern.edu
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