Re: Get fit parameters from a TGraph

I have change to
TF1 *myfunc=n->GetFunction("gaus");

and works!!

Thanks,
Julia
John Idarraga wrote:
> Hello Julia,
>
> Your fitting fuction is not "n". "n" is your TGraph. What you need
> is here:
>
> http://root.cern.ch/root/html/TGraph.html#TGraph:Fit
>
> see section, "Access to the Fit results" and "Associated functions".
> What you are trying to do is described in "Associated functions".
>
> John
>
> Campa Romero, Julia Monica wrote:
>>
>> Hi,
>>
>> I want to access to the fit parameters once a TGraph is fitted with a
>> gaussian. I am using GetFunction but it doesn't work. Bellow is my
>> program. It displays the fit parameters but then if I use GetFunction
>> as in the program bellow, it breaks when it gets the parameters.
>> Could you help me to find the errors. A piece of the program is bellow:
>>
>> *******************
>>
>> TGraph *n= new TGraph(8,sig,l);
>> n->Fit("gaus","V");
>> TF1 *myfunc=n->GetFunction("n");
>>
>> Double_t p0=myfunc->GetParameter(0);
>> Double_t p1=myfunc->GetParameter(1);
>> Double_t p2=myfunc->GetParameter(2);
>> **********************
>> Cheers,
>>
>>
>> Julia
>>
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Received on Tue Sep 28 2010 - 17:30:41 CEST