Can't Draw("p") histograms w/ more than 1878 bins

ROOT
1

Hi all,

To Draw() histograms w/ thousands of bins with markers (i.e., with the “p” option), I have to limit the number of bins displayed to <=1878…
Why?

Thanks in advance…

Kazuyoshipoints.C (397 Bytes)

points.jpg796×974 37.9 KB

2

[quote=“furutaka”]Hi all,

To Draw() histograms w/ thousands of bins with markers (i.e., with the “p” option), I have to limit the number of bins displayed to <=1878…
Why?

Thanks in advance…

Kazuyoshipoints.C[/quote]

Hmmm, I think this magic number is not important, but big number of bins is. I’ve tried to resize the canvas window with mouse and got the picture attached. If I shrink canvas back, the picture will become like yours.

hehe.png1401×868 14 KB

3

Your window along the X axis has 800 pixels. Your histogram has 2000 bins. It means you have 3 bins per pixels ! In a such case a simplified drawing algorithm is performed because, with lines or markers, it will be in any case the same…

4

Ah, I see… (sigh)

Thanks, Couet and tpochep.

Kazuyoshi

5

Well, thanks to the TGraph::TGraph(const TH1* h) constructor, I could easily draw the desired plots with markers with TGraph.

Kazuyoshi