Re: Fitting TGraphErrors

From: OKUMURA, Akira <oxon_at_ceres.phys.s.u-tokyo.ac.jp>
Date: Tue, 24 Feb 2009 21:25:52 +0900

Hello Rene,

Did you mention this?

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Note, that the linear fitter doesn't take into account the errors in x. If errors in x are important, go through minuit (use option "F" for polynomial fitting).

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I tried "F" option, but the result becomes chi^2/ndf = 0/0

Regards,

OKUMURA, Akira oxon_at_ceres.phys.s.u-tokyo.ac.jp Department of Physics, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033
TEL/FAX +81 3-5841-4173/4059
Skype : okumura.akira

On 2009/02/24, at 21:03, Rene Brun wrote:

> see comments in the doc of TGraph::Fit
> http://root.cern.ch/root/html/TGraph.html#TGraph:Fit
>
> Rene Brun
>
> OKUMURA, Akira wrote:
>> Hello ROOTers,
>>
>> I attache an example of TGraphErrors::Fit. The left plot returns
>> reasonable chi^2/ndf, but the right side doesn't. The result
>> depends on the variable "kScale" in the macro.
>>
>> The fitting results from the left and the right plots should be the
>> same value mathematically.
>>
>> Am I doing something incorrect?
>>
>> 5.22.00 + Mac OS X 10.5.6
>>
>> Regards,
>>
>> OKUMURA, Akira oxon_at_ceres.phys.s.u-tokyo.ac.jp
>> Department of Physics, The University of Tokyo
>> 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033
>> TEL/FAX +81 3-5841-4173/4059
>> Skype : okumura.akira
>
Received on Tue Feb 24 2009 - 13:25:59 CET