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Re: Lorentzian on a baseline

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  • Subject: [mg89194] Re: [mg89178] Lorentzian on a baseline
  • From: Darren Glosemeyer <darreng at>
  • Date: Thu, 29 May 2008 07:02:24 -0400 (EDT)
  • References: <>

fred.engles at wrote:
> I'm trying to fit a Lorentzian subtracted from a constant baseline,
> using findfit.
>  FindFit[rawdata, m1 - m2/((x - m3)^2 + m2^2), {m1, m2, {m3, 250}}, x,
>   MaxIterations -> 10000]
> Isn't working - either a totally flat horizantal line, or the
> subtracted 'Lorentzian' looks almost delta-function sharp. Help?
> Thanks!
> P.S. Does Experimental Data Analyst work with 6.0.1 (Mac)?

Without a reproducible example, it's not possible to say for certain 
what the problem is. My first guess would be that the default parameter 
starting value of 1 is not good for m1 or m2 and that starting values 
should be specified for those parameters.

Darren Glosemeyer
Wolfram Research

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