Re: Amoeba function [message #68745 is a reply to message #68678] |
Thu, 19 November 2009 15:25  |
b_gom
Messages: 105 Registered: April 2003
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Senior Member |
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I suspect most readers will not have the time to go through your code
and optimize it for you :), in fact I gave up trying to do a quick
read through to find out what the form of the equation is you are
trying to minimize. I can give you some of my experience with Amoeba,
however. Amoeba cannot and does not guarantee that it will find the
global minimum. The amoeba that the function is named after crawls its
way down the slope of your minimization function until it finds a
hollow to settle in. The depth of this hollow is related to the
characteristic length scale that you tell Amoeba to use, and the
starting guess for the parameters. In practice, you ultimately bear
the responsibility of judging whether Amoeba has found the best of all
possible minima.
Amoeba is a fast and useful routine for minimizing ugly complicated
data sets or functions that do not have analytical derivatives. If you
have a simple equation that you are trying to fit to a data set (even
if it doesn't have analytical derivatives), you might find other
fitting routines like MPFIT\MPFITFUN more predictable.
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