[ROOT] seed: ntuple to objects converter

From: Axel Naumann (axel@fnal.gov)
Date: Tue Nov 06 2001 - 23:50:59 MET


Hi,

having to deal with ntuple files and Root is a bit annoying: In principle
Root is perfect for using objects, but ntuples are just totally not object
oriented. MakeClass is a little help, but one still ends up with a struct.
Disadvantages:
* still no objects in sight. Usually one parses this struct and fills the
data into objects (like TLorentzVectors etc) to be able to use their
methods. Also: No inheritance, limited code reusability - none of the good
stuff that makes C++ so much nicer than FORTRAN.
* as soon as the ntuple changes (a little leaf is added somewhere in the
middle) the old MakeClass class breaks.

So I sat down and wrote a ntuple to objects converter that supersedes
MakeClass and called it "seed". It takes any ntuple and converts it into a
tree filled with objects. To make all that as easy as possible I've wrapped
the user interfaces into one class that is managing the transformation to
objects and later access of the data stored in objects.

The code is written according to ROOT's guidelines, so it smoothly
integrates with other ROOT code. The makefile supplied with the code is more
or less a copy of ROOT's makefile - with some additional changes to allow
the use of namespaces and templates.

We have tested the code for about one year now on Windows, IRIX (KCC) and
Linux (KCC, gcc).

If you feel this could be useful for you, just test it. The source is free,
open, a present, no strings attached. You can find the source, documentation
and contacts for help at

http://www-d0.fnal.gov/nikhef?seed

I'm looking forward to getting your feedback!

Cheers,
Axel.



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