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Re: Powell's ghost [message #7187]

Fri, 04 October 1996 00:00

Mark Fardal
Messages: 51
Registered: October 1995

Member

As the function I need to minimize gets slower and slower, I've been
looking more closely at what POWELL does. What a piece of garbage.
The ITMAX and FTOL keywords are both ignored completely, and so it
merrily goes off and minimizes my function to 1 part in 10^12 when
I told it 10^-4 error was all right. Peter Mason points out to me
that this is "core IDL" (thanks Peter), so I can't even get to the
code to fix it.

The evaluated function is the main source of my current fitting
problems, but the excess accuracy in POWELL is sure slowing me down.
Does anyone have a properly implemented version of this or another
multidimensional minimization routine? I can only use ones without
analytic derivatives.

Thanks,

Mark Fardal
University of Colorado

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		Re: Powell's ghost By: Mark Fardal on Fri, 04 October 1996 00:00
		Re: Powell's ghost By: hto on Fri, 04 October 1996 00:00

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