Talks, verbal reports

• Status report on geometry and global tracking filter: Daniel Whiteson.
  
  • Full offline geometry gives substantially better performance (e.g., number of smt hits, impact parameter) than any of the simple RCP-based geometry options.
  • Robert Illingworth has started work on an L3 implementation for offline tracking geometry.
  • Performance improved by allowing 7-hit cft tracks that have at least 3 hits in smt.
  • The efficiency/rejection purely on central muon triggers would be nice to know.
  • Daniel will investigate how much work would be involved in modifying code to allow axial-only cft tracks to be matched to 3-D silicon information. This is the only way of getting the track-based primary vertex finder going in the near future. At the moment there is a flag "do_stereo", which works only if 3-D tracks are available from cft. If do_stereo is false then all tracking is done in r/phi only.
• Status report on L3 muons: Martijn Mulders.
  • Both the new unpacker and the fix for the muon_geometry memory leak made it into p11.04.
  • Unfortunately, other changes to the offline muon software have prevented p11.04 certification even starting:
    • Thursday's build crashed because of an uninitialized variable _useDB in the MDT code.
    • Friday's build suffers from a huge memory leak, probably in the muon segment finding. This is very difficult to debug because a very large number of offline muon packages have been changed in p11.04.
  • There followed a long discussion about what to do in the short term:
    • Make sure that basic tests of L3 memory usage, timing and efficiency are part of the standard testing required before the offline muon group releases code to the production branch.
    and in the long term:
    • We need a serious cost/benefit analysis of retaining/breaking the link of L3Muon to the offline code.
    • We need to try and get back to the idea of development occuring in the test branch and being allowed only in exceptional circumstances in the production branch. But, of course, if we're honest we want to do the following developments that we don't want to wait for p12 in June:
      • Finish L3Muon
      • Central tracking (including L3 implementation of offline geometry).
      • Modifications to l3fanalyze so that it dynamically recognises which tools have run. (This is necessary to get l3fanalyze run as part of standard data processing on the offline farms.)
      • If it is decided to switch on streaming online this would require additional changes.
• Other discussion: Plans for L3 NADA will be presented by Marumi Kado next week. Issues include: Should the "offline" code be run in L3 or should we maintain our own version? How should parameters controling the operation of the algorithm be input? (Not as .rcp parameters if they are likely to need to change month by month as detector performance changes.)

Scribe: Terry Wyatt.