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Subject: Re: 3d surface fitting
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> Modeling is a sometimes tricky thing, as you
> are finding. It sounds like your data has some
> problems. Why does data always come out that
> way? ;-)

I don't know, but there should be a statistical law about
the errors of experimentation.... as oppossed to just "being
careful". :)

I'm really thankful for your (yet another) tip about
fminspleas. Reducing it to a 3 NLP fit already starting
giving me the right bessel form, but still couldn't do it
well for half the datasets.

After that I used the built-in weighting options to focus
mainly on the central lobe, and now the fits work for
(almost) all the datasets! :-)

I'm not sure I really understand though what fminspleas does
different from lsqcurvefit. They both seem to solve problems
in a least square sense, but the main difference seems to be
in the way the parameters are handled/prioritized. 

However, I couldn't really understand why it is faster or
more effective?

Thanks again! :) A real pleasure to talk with an 'expert'.