RE: Using Parameters in TTreeFormula's?

From: Philippe Canal <>
Date: Wed, 11 Oct 2006 13:38:24 -0500

Hi Robert,

How will you actually use this feature? Do you plan on minizing for each individual events or do minimize for all events?


-----Original Message-----
From: [] On Behalf Of Robert Feuerbach
Sent: Wednesday, October 11, 2006 10:42 AM To:
Subject: [ROOT] Using Parameters in TTreeFormula's?


Are there plans to permit normal TFormula parameters in an expression using a TTreeFormula? For instance, I'd like to write something like:

TTreeFormula totEdiff("totEdiff",


where 'electronP', 'preshowerE' and 'showerE' are simple leafs in tree. This can be done in TFormula's, but does not appear to work in TTreeFormula's. In TTreeFormula::DefinedVariable fNpar is set to 0 and the class never looks back.

I'm trying to write a general routine to minimize expressions in terms of tree variables by varying the set of parameters, but the TTreeFormula's are completely unaware of the normal '[0]'-like parameters. I know it can by minimized by writing a macro using TFitter and TMinuit directly, but I'd like to have a more general implementation since this is common task. It could even evolve into a TTree::Minimize kind of method.

Thank you,
Rob Feuerbach


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Received on Wed Oct 11 2006 - 20:46:02 MEST

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