Groups > comp.graphics.apps.gnuplot > #2288

fitting from x to y and from y to x

Newsgroups	comp.graphics.apps.gnuplot
Date	2014-02-04 01:29 -0800
Message-ID	<ff8c63b2-6c6a-406f-b109-53e535b59ddd@googlegroups.com> (permalink)
Subject	fitting from x to y and from y to x
From	Jean Dupont <jeandupont115@gmail.com>

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It happens quite often that one is measuring two data sets, lets call them x and y. It's common also to have a measurement error on x (delta_x) and on y (delta_y).
Then a fitting on f(x) with some parameters (a, b, c...)is performed using delta_y
which when done properly will give reliable values for a, b, c...
It's also interesting however to fit the inverse function of f(x) with y as independent variable and x as dependent variable using delta_x in the fitting.
This will give slightly different values for a,b,c ...One could then take the mean
of both sets a,b,c for an end-result.

I was wondering whether the procedure above can be implemented elegantly in Gnuplot without having to calculate the inverse function explicitly first.


kind regards,
jean

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fitting from x to y and from y to x Jean Dupont <jeandupont115@gmail.com> - 2014-02-04 01:29 -0800
  Re: fitting from x to y and from y to x Karl <mail.kfr@gmx.net> - 2014-02-04 13:05 +0100
    Re: fitting from x to y and from y to x Jean Dupont <jeandupont115@gmail.com> - 2014-02-04 06:57 -0800
  Re: fitting from x to y and from y to x Ethan A Merritt <merritt@u.washington.edu> - 2014-02-04 12:06 -0800
    Re: fitting from x to y and from y to x Jean Dupont <jeandupont115@gmail.com> - 2014-02-05 06:59 -0800
      Re: fitting from x to y and from y to x Ethan A Merritt <EAMerritt@gmail.com> - 2014-02-05 08:12 -0800
        Re: fitting from x to y and from y to x Jean Dupont <jeandupont314@gmail.com> - 2014-02-06 11:54 -0800

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