N-dim histo

ROOT
#1

Hi,

I’d like to histogram N dimensional data (N=4 for now). I can’t find any clean way of doing that, other than a plain 4dim array of floats. Should I add a THn, deriving from TH1, or does something like that already exist?

Axel.

#2

Axel,

I suggest using a tree and the possibility to draw 4-D from TTree::Draw
t.Draw(“t:z:y:x”);
produces a 3-d scatter-plot with marker colors corresponding to the variable t
see doc of TTree::Draw

Making a TH4 does not make much sense as you will quickly exhaust your RAM.

Rene

#3

Hi Rene,
Good point, thanks.
Axel.