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Re: [Gnuplot-info] Fitting
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From: Ethan A M. <eam...@gm...> - 2018-08-02 15:40:35
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On Thursday, 02 August 2018 12:58:24 Patrick Dupre wrote: > Hello, > > I have data with error bars on x and y. > To fit them properly, i.e., by weighting the data, I need to convert > the x error bar in y error bar. > To do this I need to calculate the derivative of the fitting function. > To make it right I need to calculate this derivative at each iteration and > then to calculate the new error bars. > It possible to do it with gnuplot? Gnuplot can handle data with separate error estimates on x and y. >From the documentation in "help fit" A few shorthands for the `errors` qualifier are available: `yerrors` (for fits with 1 column of independent variable), and `zerrors` (for the general case) are all equivalent to `errors z`, indicating that there is a single extra column with errors of the dependent variable. `xyerrors`, for the case of 1 independent variable, indicates that there are two extra columns, with errors of both the independent and the dependent variable. In this case the errors on x and y are treated by Orear's effective variance method. There is a worked example of use in the fit demo. Ethan > Thank. > > =========================================================================== > Patrick DUPRÉ | | email: pd...@gm... > Laboratoire de Physico-Chimie de l'Atmosphère | | > Université du Littoral-Côte d'Opale | | > Tel. (33)-(0)3 28 23 76 12 | | Fax: 03 28 65 82 44 > 189A, avenue Maurice Schumann | | 59140 Dunkerque, France > =========================================================================== > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > gnuplot-info mailing list > gnu...@li... > Membership management via: https://lists.sourceforge.net/lists/listinfo/gnuplot-info |
