Hi Olivier,
Thank you very much for this little trick.
It works perfectly.
Ciao,
Andreas
Olivier Couet wrote:
> Hi Andreas,
>
> Here is what you want:
>
> void ticks()
> {
> gROOT->Reset();
> TCanvas* c1 = new TCanvas("c1","Modulation");
>
> int NPoints = 360;
> TGraph* gr = new TGraph(NPoints);
>
> for (int i = 0; i < NPoints; ++i) {
> double x = i*360.0/NPoints;
> double y = 100 + 50*cos(2*x*TMath::Pi()/180);
> gr->SetPoint(i, x, y);
> }
>
> TH1F *h1 = new TH1F("a","a",1000,0,360);
> gr->SetHistogram(h1);
> gr->Draw("AC");
> c1->Update();
>
> gr->GetHistogram()->SetXTitle("Azimuthal scatter angle");
> gr->GetHistogram()->SetYTitle("Counts");
> gr->GetHistogram()->SetAxisRange(0, 200, "Y");
> gr->GetXaxis()->SetNdivisions(-504);
> c1->Modified();
> }
>
> Explanation: TGraph creates internally an histogram to draw the graph.
> That is the one you get when you do gr->GetHistogram(). That histogram has
> by default 100 bins. In your case a 100 precision is not enough and you
> see that "bin size effect". In this modified version of your macro I book
> an histogram with 1000 bins and give it to the TGraph using
> gr->SetHistogram. Having done that you do not need to set the X range of
> the TGraph.
>
> Cheers, Olivier
--
Andreas Zoglauer
MPI fuer extraterrestrische Physik Phone: +49/89-30000-3848
Postfach 1312 Fax: +49/89-30000-3569
85741 Garching, Germany Email: zog@mpe.mpg.de
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