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MPfit question [message #62623]

Tue, 30 September 2008 07:38

Wox
Messages: 184
Registered: August 2006

Senior Member

Hi all,

I'm using the wonderfull mpfit routine from Craig Markwardt. Today I
was having problems with convergence and I was looking in the code
what caused it. I was using parameter limits and as far as I can tell,
the parameter incrementation is done like this:

xnew = x + alpha * dx

where dx are the parameter increments and alpha = 1, except when xnew
would exceed the limits, in which case alpha < 1. So if one parameter
is close to the limit, this effects the increments for all other
parameters. If alpha is too small, the fit stops.

Why isn't dx adapted, so that pegged parameters won't effect the
convergence for other parameters?

Wout

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[Message index]

		MPfit question By: Wox on Tue, 30 September 2008 07:38
		Re: MPfit question By: Craig Markwardt on Thu, 02 October 2008 08:59
		Re: MPfit question By: Wox on Thu, 02 October 2008 04:39
		Re: MPfit question By: Craig Markwardt on Wed, 01 October 2008 10:16
		Re: MPfit question By: Wox on Wed, 01 October 2008 01:31
		Re: MPfit question By: Craig Markwardt on Tue, 30 September 2008 08:49
		Re: MPFIT question By: Craig Markwardt on Tue, 13 January 2009 22:41
		Re: MPFIT question By: j.coenia@gmail.com on Wed, 14 January 2009 07:54
		Re: MPFIT question By: j.coenia@gmail.com on Thu, 15 January 2009 08:17
		Re: MPFIT question By: Craig Markwardt on Fri, 16 January 2009 22:10
		Re: MPFIT question By: Craig Markwardt on Wed, 14 January 2009 23:52
		Re: MPFIT question By: pgrigis on Wed, 14 January 2009 14:08
		Re: MPFIT question By: j.coenia@gmail.com on Wed, 14 January 2009 13:37
		Re: MPFIT question By: Craig Markwardt on Wed, 14 January 2009 08:23

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