How to make stat box appear

[Ricardo_Lambo]

Hello Forum Colleagues,
I believe the usual way to make the stat box with the fit parameters and stats is to use the command “gStyle->SetOptFit(1)”. However, it seems to have no effect on the section of the code below:

gROOT->SetStyle("Plain");   //set plain TStyle
gStyle->SetOptStat(0); //draw statistics on plots, 0 for no output
gStyle->SetOptStat(111111); //draw statistics on plots, 0 for no output
gStyle->SetOptFit(1);    //draw fit results on plot, 0 for no output
gStyle->SetPalette(57);     //set color map
gStyle->SetOptTitle(0);    //suppress title box


TCanvas c;


// draw fit including the error band
c.Divide(2, 2);
for (unsigned i = 0; i < nmodels; ++i) {
    c.cd(i + 1);
    models[i]->DrawFit();
}
c.Print("/home/riclambo/Desktop/bat_27_06_345/C6_data/data-all-band.pdf");

// draw data and all fits in the same plot (w/o error bands)
c.Clear();
c.cd(1);

gr.SetMarkerStyle(20);
gr.SetMarkerSize(.5);
gr.GetXaxis()->SetTitle("cos(#theta)");
gr.GetYaxis()->SetTitle("C6 (meV #AA^{6})");
gr.Draw("ap");

for (unsigned i = 0; i < nmodels; ++i) {
    models[i]->GetFitFunction().SetLineColor(i + 1);
    models[i]->GetFitFunction().SetLineWidth(2); 
    models[i]->GetFitFunction().GetXaxis()->SetTitle("cos(#theta)");
    models[i]->GetFitFunction().GetYaxis()->SetTitle("C6 (meV #AA^{6})");
    models[i]->GetFitFunction().Draw("l same");

    double chi2_models = models[i]->CalculateChi2(models[i]->GetBestFitParameters());
    double pvalue_models   = models[i]->CalculatePValue(models[i]->GetBestFitParameters());

    cout << "model_chi2" << "\t" << i << "\t" << chi2_models << endl; 
    cout << "pvalue" << "\t" << i << "\t" <<pvalue_models << "\n" << endl ;

      }
    c.Print("/home/riclambo/Desktop/bat_27_06_345/C6_data/data-all.pdf");

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_ROOT Version: 6.24
_Platform: Ubuntu
Compiler: Not Provided

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[couet]

@Ricardo_Lambo

gr.Draw("ap");

It seems you draw a TGraph, a TGraph has no stats.

[Ricardo_Lambo]

Is there a way that I can make the stats appear on the graph? using something like:

  TPaveStats *ps = (TPaveStats* ) g->GetListOfFunctions()->FindObject(“stats”);

[couet]

As I said a TGraph has no stats, you cannot make appear something which does not exist. Only histograms have stats.

[RENATO_QUAGLIANI]

The poor man workaround would be something like this and Draw the TH1D.
See Convert TGraph to TH1 histogram
However I suspect you will need tweaks to do on the conversion routine if you need to make some sort of error setting or configure weights on th1D.

[Wile_E_Coyote]

@couet Maybe an example of how to manually create (and draw) a TPaveStats, with fit statistics for a (fitted) TF1, would be helpful.

[couet]

Yes for the TGraph fit results it works, the fit box is created:

void graphfit()
{
   gStyle->SetOptFit(1);
   Double_t x[] = {1., 2., 3.};
   Double_t y[] = {2., 3., 2.};
   auto g = new TGraph(3, x, y);
   g->Fit("gaus");
   g->Draw("A*");
}

[Wile_E_Coyote]

So, we’re back to the original problem … why can the “stats” be missing?

@Ricardo_Lambo I guess one would need to inspect the “DrawFit” method.
Just to make sure … remember that the “stats” box is “attached” to the graph and NOT to the “fit function”. Moreover, you need to really draw the graph to create its “stats” box. I do not have any example of how to manually create (and draw) a TPaveStats (with fit statistics) when drawing a “fit function” alone.

[couet]

with this example they are not missing:

void graphfit()
{
   gStyle->SetOptFit(1);
   Double_t x[] = {1., 2., 3.};
   Double_t y[] = {2., 3., 2.};
   auto g = new TGraph(3, x, y);
   g->Fit("gaus");
   g->Draw("A*");
   gPad->Update();
   TPaveStats *st = (TPaveStats*)g->GetListOfFunctions()->FindObject("stats");
   st->ls();
}

Processing graphfit.C...

****************************************
Minimizer is Minuit / Migrad
Chi2                      =  3.19935e-07
NDf                       =            0
Edm                       =  6.39931e-07
NCalls                    =           71
Constant                  =      3.00056   +/-   1.00004     
Mean                      =            2   +/-   0.435822    
Sigma                     =      1.11018   +/-   0.658012     	 (limited)
Info in <TCanvas::MakeDefCanvas>:  created default TCanvas with name c1

OBJ: TPaveStats	stats  	X1= 2.360000 Y1=2.852500 X2=3.440000 Y2=3.152500

[Ricardo_Lambo]

Thanks @Wile_E_Coyote @RENATO_QUAGLIANI @couet. I was able ot use the last solution to make the stats I wanted appear on the graph.