Re: Problems with Histograms
Rene Brun (Rene.Brun@cern.ch)
Sat, 12 Dec 1998 11:07:25 +0100
Robert Willson wrote:
>
> I'm just beginning with root, so please excuse the ignorance. Here's my
> file:
>
> void newprog() {
>
> c1 = new TCanvas("c1", "Stupid", 20, 10, 800, 600);
> pad1 = new TPad("pad1", "First", 0.02, 0.7, 0.97, 0.97, 17, 3);
> pad2 = new TPad("pad2", "Second", 0.02, 0.4, 0.97, 0.65, 17, 3);
> pad3 = new TPad("pad3", "Third", 0.02, 0.02, 0.97, 0.35, 17, 3);
>
> pad1.Draw();
> pad2.Draw();
> pad3.Draw();
>
> TH1F *histo1 = new TH1F("Num1", "0.0001", 100, 0.0, 100.0);
> TH1F *histo2 = new TH1F("Num2", "0.00001", 100, 0.0, 100.0);
> TH1F *histo3 = new TH1F("Num3", "0.000001", 100, 0.0, 100.0);
> Double_t x, w1, w2, w3;
>
> for (x=0.0; x<100.0; x=x+1.0) {
>
> w1 = 3.0 - x*x + 10.0*x + 0.01*x*x*x - 0.0001*x*x*x*x;
> w2 = 3.0 - x*x + 10.0*x + 0.01*x*x*x - 0.00001*x*x*x*x;
> w3 = 3.0 - x*x + 10.0*x + 0.01*x*x*x - 0.000001*x*x*x*x;
>
> histo1.Fill(x,w1);
> histo2.Fill(x,w2);
> histo3.Fill(x,w3);
>
> }
>
> pad1.cd();
> histo1.Draw("C");
> pad2.cd();
> histo2.Draw("C");
> pad3.cd();
> histo3.Draw("C");
> }
>
> The first histogram is plotting, but the second and third are not. Any
> suggestions?
>
> Thanks,
>
> Robert Willson
> willson@pacific.mps.ohio-state.edu
Hi Robert,
Your histograms 2 and 3 have negative contents. This gives problems
with the Draw("C") option. Use no option Draw() or Draw("L")
and you will see your histograms.
Rene Brun