rDST

Original idea: reduced data summary format as input for the stripping jobs

Task force: O.Callot, M.Cattaneo (convener), M.Frank, C.Jones, P.Koppenburg, T.Ruf

List of presentations:

• December 2004, LHCb week,   Computing Model: report of the CM task force, Nick Brook
• February 2005, T-Rec meeting,  rDST working group, Marco Cattaneo
• March 2005, Software week,     rDST proposal (+discussion), Marco Cattaneo
• March 2005, LHCb week,         rDST format & plans, Marco Cattaneo

Summary of rDST size reduction (March 2005):

1. Starting point, DC04 rDST objects (except Calo info which only contributes <5 kB)
   • 71.1 kB
2. Filtering of unnecessary states and measurements
   • 22.0 kB
3. Optimised for Root compression (float)
   • 10.5 kB
4. Pack into int
   • 7.7 kB

Observation:
Step 1. is specific to rDST.
            Could also be more selective, for example for J/psi or D* stream, store only info related to reconstructed  J/psi or D* candidates.
Steps 2., 3. can (optionally) apply to any SIM, DST object
 

Releases:

Links to latest LHCb doxygen web (all in Event/PackedEvent package, except for StandardPacker which is in Kernel/LHCbKernel)

http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_standard_packer.html

Packed event classes:
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/struct_packed_collision.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/struct_packed_m_c_particle.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/struct_packed_m_c_vertex.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/struct_packed_track.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/struct_packed_tr_state_l.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/struct_packed_tr_state_p.html

Algorithms to pack the classes
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_pack_collision.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_pack_m_c_particle.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_pack_m_c_vertex.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_pack_tr_stored_track.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_pack_tr_state_l.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_pack_tr_state_l.html

Algorithms to unpack the classes
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_unpack_collision.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_unpack_m_c_particle.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_unpack_m_c_vertex.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_unpack_tr_state_l.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_unpack_tr_state_p.html
http://lhcb-release-area.web.cern.ch/LHCb-release-area/LHCB/doc/html/class_unpack_tr_stored_track.html

For MCParticles/MCVertices, the packed classes are used on the Boole and Brunel output of the latest versions.

The next step requires input from physics analysis team to develop and test the packed classes for the complete Brunel output, as well as the rDST filtering (removal of unnecessary containers, removal of coords and states from tracks etc.) for the stripping program.