Hi Hermine,
An example with two options. Uncomment the line with one of the options.
Rene Brun
#include "TH1.h"
#include "TF1.h"
Double_t fitf(Double_t *x, Double_t *par)
{
Double_t arg = 0;
if (par[2]) arg = (x[0] - par[1])/par[2];
Double_t fitval = par[0]*TMath::Exp(-0.5*arg*arg);
return fitval;
}
void myfit()
{
TH1F *hpx = new TH1F("hpx","px distribution",100,-4,4);
hpx->FillRandom("gaus",25000);
// Creates a Root function based on function fitf above
TF1 *func = new TF1("fitf",fitf,-2,2,3);
//func->SetLineColor(kRed); //OPTION 1
// Sets initial values and parameter names
func->SetParameters(100,0,1);
func->SetParNames("Constant","Mean_value","Sigma");
// Fit histogram in range defined by function
hpx->Fit("fitf","r");
//hpx->GetFunction("fitf")->SetLineColor(kBlue); //OPTION 2
}
Hermine Katharina Woehri wrote:
>
> Hello,
>
> Into one pad I would like to draw 4 sets of data points, which I would
> like to fit. In order to additionally draw error bars, I set the
> MarkerSize of the histogram-points to zero and used the TGraphErrors() to
> draw the measured values with their error bars. The usage of filling a
> histogram was necessary in order to fit the data points. With
> SetMarkerColor for the TGraphErrors()-object I can select different
> colours for the data points.
> But, HOW, can I select different colours for the fitted curves?
> (hist1->SetColorLine(kBlue); does not work !).
>
> Cheers,
>
> Hermine
>
> +------------------------------------------------------+
> |Hermine Katharina Woehri hermine.woehri@cern.ch |
> +------------------------------------------------------|
> |EP Division |
> |CERN |
> |CH-1211 Geneve 23 office: +41 22 767-9408|
> |Switzerland private: +33 671 72 9888|
> +------------------------------------------------------+
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