Problem with TTree->Draw()!?

ROOT
1

So here is the plot of a data using TGraph and TTree. I don’t understand what are those spikes on the curve?

g.jpg696×472 9.83 KB


t.jpg696×472 11.3 KB

2

I am afraid that we cannot do much without having a small data file and the command generating your plot> It could be just a binning effect.

Rene

3

Thanks for reply. Here is the data. The commands also are as following:

TTree t;
t.ReadFile(“DD_WS.txt”,“x/D:y/D”);
t.Draw(“x”,“y”,“C”);

TGraph tg(“DD_WS.txt”);
tg.Draw(“AC”);
DD_WS.txt (965 Bytes)

4

What you observe is a simple binning effect due to your x values.
You can solve the problem by forcing the range as follows

TTree t; t.ReadFile("DD_WS.txt","x/D:y/D"); t.Draw("x>>h(100,0,100)","y","C"); or

TGraph g("DD_WS.txt"); g.Draw("ac");
Rene

5

Thanks man.