Re: [ROOT] fitting in TProfile2D

From: Rene Brun (Rene.Brun@cern.ch)
Date: Thu Apr 10 2003 - 22:38:04 MEST


Hi Martin,

Could you send me a file with your TProfile2D and also clarify
which version of Root?

Rene Brun

On Wed, 9 
Apr 2003, Martin Schroedter wrote:

> Hello,
> 
> I am reasonably sure that the fitting of 2-d function in TProfile2D 
> does not work correctly. The fit is wrong and the combined plot that is 
> automatically produced is a black-white 2-d scatter plot. All further 
> calls to hprof2d->Draw("cont") produce black and white 2-d scatter 
> plots.
> 
> In general, how does one go about doing multidimensional fitting in 
> ROOT?
> 
> Thank you,
> 	Martin
> 
> hprof2d  = new TProfile2D("hprof2d","Width ",40,2,6,40,0,1,-1,2);
> tree->Draw("energy:width:size>>hprof2d");
> TF2 *func2 = new TF2("func2",fitf2d,2,6,0,1,3);
> func2->SetParameters(-2,.7,.1);
> hprof2d->Fit("func2","r");
> 
> Double_t fitf2d(Double_t *x, Double_t *par)
> { return par[0]+par[1]*x[0] + par[2]*x[1]; }
> 



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