I am trying to make a function describing the response of a photomultiplier tube, for fitting to measurements. As this is quite an extensive function, I would like to use “subfunctions”. What I mean is the following:
TF1 *f1 = new TF1("f1","*TMath::Exp(*x)"); TF1 *PMTresp = new TF1("PMTresp","+f1");
However, the parameter  in PMTresp should be the same as  in f1. I noticed that via the code above ROOT will assign new parameters  and  to f1.
Is there a way to tell ROOT? Or can I afterwards say that  and  are the same parameter?
Thanks in advance!