Groups > comp.graphics.apps.gnuplot > #363

trying to get a fit to work.

From	aviphysics <aviphysics@gmail.com>
Newsgroups	comp.graphics.apps.gnuplot
Subject	trying to get a fit to work.
Date	2011-06-07 16:32 -0700
Organization	http://groups.google.com
Message-ID	<62b76acf-a50c-49f2-a02a-908398651e5b@q12g2000prb.googlegroups.com> (permalink)

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So I got this HPLC peak that I am trying to fit a exponentialized
Gaussian to. It fits decently in Mathematica but trying to fit it in
gnuplot yields "Undefined value during funtion evaluation"

The equation is
modeltwo(x) = 1/(2*tau)*exp(sigma**2/(2*tau**2)-(x-em)/
tau)*erfc(sigma/
(sqrt(2)*tau)-(x-em)/(sqrt(2)*sigma))

Here is a plot using the starting constants
http://i283.photobucket.com/albums/kk302/keyserthomas/plot.jpg

em=10
sigma=2.3
tau=4.98

Any ideas what the problem might be?

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Thread

trying to get a fit to work. aviphysics <aviphysics@gmail.com> - 2011-06-07 16:32 -0700
  Re: trying to get a fit to work. Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2011-06-08 23:02 +0200
  Re: trying to get a fit to work. sfeam <sfeam@users.sourceforge.net> - 2011-06-08 21:48 -0700
    Re: trying to get a fit to work. Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2011-06-09 22:26 +0200
      Re: trying to get a fit to work. sfeam <sfeam@users.sourceforge.net> - 2011-06-09 18:29 -0700

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