[Pytables-users] Variable length collections of user's structures

[Sebastien B. <bi...@ce...>]

Hi there,

I noticed the PyTables conference at CERN and I was wondering:
 from the examples of the PyTables package, one can easily figure out
 how to define a nested structure of structures of... etc...

But is there a way to define a column of user tables.IsDescription ?
Something like that:

class Vertex(IsDescription):
 position = FloatCol( dflt=0., shape=3 )

class Particle(IsDescription):
 fourMomentum = FloatCol( dflt=0., shape=4 )
 idCode       = IntCol( dflt=0, shape=1)
 productionVtx= Vertex()
 decayVtx     = Vertex()

class Particles(IsDescription):
 particles = MakeCol(Particle) #<== here is the tricky part

class Event(IsDescription):
 electrons = Particles()
 photons   = Particles()
 neutrinos = Particles()

An Event is hence made from several collections of particles which are
themselves made from a production and a decay vertices, a four-momentum
and some barcode to distinguish between different types of particles.

Of course I don't know a priori the number of electrons and photons I can
find in each of my events...

Any hint on how to model this event structure ?

Cheers,
Sebastien.
--
###################################
# Sebastien Binet                 #
# Lawrence Berkeley National Lab. #
# 1 Cyclotron Road                #
# Berkeley, CA 94720              #
###################################