From bcasey@fnal.gov Fri Apr 30 14:48:00 2004
Date: Fri, 16 Apr 2004 22:55:34 -0500
From: bcasey@fnal.gov
To: d0dfwg@fnal.gov
Cc: d0-conveners@fnal.gov
Subject: common format

Herb et al,

I raised a point at the conveners meeting a few weeks ago about the
charge of your group and it seems to have been forgotten so I'd like to
raise it again.

I think for your working group to be successful, it must figure out why
people are using different formats and solve that with one format.

I think the main reason different formats exist is so that people can
run high level algorithms with their own choice of inputs that only run
in a particular format or only accept inputs in a particular format.
Specifically kinematic fitters.

For instance, in a lifetime analysis, it makes much more sence to first
reconstruct a particle, find its secondary vertex, then find a primary
vertex explicity excluding secondary tracks from the primary vertex,
than to try and use vertex information computed globally for the entire
event.  This requires a vertexing package.  There is no supported
vertexing package included in the tmb_tree format.  So people who do
root based lifetime studies move to the d0root format.

So if these tools or algorithms are not incorporated in the new format,
people will simply convert the new format to the more familiar formats
so that they can use the existing tools.

I think the success of this endevor completely relies on incorporating
all these user level tools into the single format.

By incorporating, I mean a user would add one #include statement to
their analysis program to access a tool, not have to check out half the
Chicago phone book worth of code and compile it in their own area to
access it.

Brendan