Hi Steven,
For making a TGraph out of a TTree, see section:
"How to obtain more info from TTree::Draw"
in the documentation of TTree::Draw at:
http://root.cern.ch/root/htmldoc/TTree.html
Concerning your question about making a TGraph out of a TF2,
I do not understand what you mean. There is a mismatch with dimensions.
Rene Brun
steven staelens wrote:
>
> root Version 3.05/01 on Intel Linux RH 7.1
>
> Hi ,
>
> In addition to a former mail I narrowed my problem down to the
> following:
>
> I have fitted a twodimensional function to a twodimensional histogram as
> it should following ROOT user guide lines. The fit seems to be OK, but
> to be really sure I have to plot it on top of the lego plot of the
> histogram. When I do so, the maximum value of my histogram is set equal
> to the maximum of my 2D fit. In my case, this is absolutely not
> wanted. I've read on the ROOT digest that this is normal and that it
> can be solved by using a MultiGraph.
>
> Being a ROOT newbie however I don't know how to switch the drawings of
> my TF2 and of my TH2F into a TGraph. I've tried in the following
> pathetic way:
>
> TGraph *f2D = new TGraph()
> h2D->Draw(">>t1")
>
> but I realize this is not the way it should be.
>
> Can somebody perhaps help me out by giving an example on how to change a
> 2D histogram drawing into a TGraph object and the same question for a
> twodimensional function. When this is solved I can then easily do:
>
> TMultigraph *mg = new TMultiGraph()
> mg->Add(gr1)
> mg->Add(gr2)
> mg->Draw()
>
> and my problem will be solved.
>
> Thanks in advance,
>
> best regards,
>
> Steven
>
> S. Staelens
> Ghent University
> ELIS / Medisip
> Proeftuinstraat 86
> B-9000 Gent
> tel. 0032 9 264 66 28
> fax. 0032 9 264 66 18
> email: Steven.Staelens@rug.ac.be
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