Improving ab initio computational speed

From: Laurence Lavelle <lavelle (+ at +) mbi.ucla.edu>
Subject: Improving ab initio computational speed
Date: Sat, 08 Nov 1997 19:05:12 -0800

Two possible ways to speed up ab initio calculations are:

1) Use a bases set with fewer bases functions first. Then, after convergence, use a bases set with more bases functions. Repeat this process until convergence is obtained with the (largest) bases set that was originally intended.

2) Use the largest bases set with a higher 2e integral cuttoff point (e.g. 10^-7 Hartree) and after convergence decrease the 2e integral cuttoff point. Repeat until convergence is obtained with the originally intended 2e integral cuttoff point (e.g. 10^-11 Hartree).

Do either of these approaches have potential downfalls. Is one approach better than the other?

Thanks
Laurence Lavelle

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Laurence Lavelle, Ph.D.
University of California Los Angeles
Molecular Biology Institute, and Department of Chemistry & Biochemistry
Laboratory of Structural Biology & Molecular Medicine
Los Angeles, CA 90095-1570, USA

Email:LAVELLE (+ at +) MBI.UCLA.EDU
Phone (Lab): (310) 206-8270
Phone (Office): (310) 825-2083
Fax: (310) 267-1957
http://www.doe-mbi.ucla.edu/people/lavelle/lavelle.html
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