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HI David, It turns out the tracking tutorial was wrong, TPCReco just
finds tracks but it doesn't fill them into the Event header. Other than
that your code is fine. I have updated the documentation at: 

http://www-sldnt.slac.stanford.edu/jas/documentation/lcd/tutorial5/defau
lt.htm

to show the correct way of calling the tracking code, and of looking at
the results. Mike has promised more documentation on the Track Finder
soon!

Tony

-----Original Message-----
From: David L. Wagner, University of Colorado
[mailto:[log in to unmask]]
Sent: Tuesday, April 13, 1999 11:23 AM
To: Tony Johnson
Subject: Tracking


Hi Tony,

Just a quick question; if you don't know off the top of your head, I'll
just ask at the meeting this afternoon.  How exactly does one get at the
tracks that one reconstructs?  I followed the tutorial and made a driver
which just adds a new hep.lcd.recon.tracking.tpc.TPCReco() to the list
of
processors to run.  That seems to work fine.  But when I have an
analysis
program that does the following:

  LCDEvent header = (LCDEvent) d;
  TrackList tracklist = header.getTrackList();

(where d is the EventData object passed to processEvent(), as in the
tutorial) I just get an "EventException: Key TrackList not found in
EventHeader".  The following code in the same analyzer works fine, by
the
way:

  LCDEvent header = (LCDEvent) d;
  CalorimeterHits hits = header.getEMCalorimeterHits()

Can one run two consecutive programs like that (a driver followed by an
analyzer)?  I looked at the code for how the event display draws tracks,
and it seemed like my code looked reasonable.

Thanks,

-David