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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