RE: [ROOT] how draw the .M() of the sum of TLorentzVector

From: Philippe Canal (pcanal@fnal.gov)
Date: Tue Jun 15 2004 - 19:41:41 MEST


Hi,

You can not call any overloaded C++ operators from TTreeFormula.
Hence (p4_pi1_eta_rec_fit + p4_pi2_eta_rec_fit) is not a valid TTreeFormula expression.
In addition, TTreeFormula can currenlty only call function that takes and returns 
numerical values.

Cheers,
Philippe.

-----Original Message-----
From: owner-roottalk@pcroot.cern.ch
[mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of Francesco Perfetto
Sent: Tuesday, June 15, 2004 10:45 AM
To: roottalk@pcroot.cern.ch
Cc: rene.brun@cern.ch
Subject: [ROOT] how draw the .M() of the sum of TLorentzVector


Hi all,

I would like add 2 or more TLorentzVector for then take the .M().
After I open my root file with TBrowser in which there are the
TLorentzVector I do at command line:

root [1] .L $ROOTSYS/lib/libPhysics.so
root [2] res->Draw("(p4_pi1_eta_rec_fit + p4_pi2_eta_rec_fit).M()")

(WHERE p4_pi1_eta_rec_fit. and p4_pi2_eta_rec_fit. are 2 my
TLorentzVector)

but I have the following error:

*ERROR 30 :
 Bad numerical expression :"(p4_pi1_eta_rec_fit+p4_pi2_eta_rec_fit).M()"
root [3]

There is anyone that can help me?

Thanks in advance.
Francesco.



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