DD4hep meeting 22/10/2020
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A.Sailer, C.Vuosalo, F.Gaede, M.Frank, G.Hugo, M.Petric

1)   Pending problems

1.1  Pending problems reported by Sang Hyun Ko:
   - Cannot setup Birk's constant as material property.
   - No analogy to G4PVParametrized. Unclear if a solution is possible.
1.3  Change of unit system to Geant4 units: On Hold.
1.4  Problems with scaled shapes (Issue 750)
1.5  Possible improvements for checking/linker compiler flags for different compilers (gcc, clang)
     See also Marko's report.
1.6  Pending PR request to include module using PODIO and EDM4hep.
     Work in progress by Frank.

2)   Closed issues and fixed problems

2.1  Problems reported by Sang Hyun Ko:
   - Significant CPU overhead using colors in DDG4.
   - Adding many daughters to a volume is very time consuming up to non-usability.
2.2  Reflections solved and tested by CMS. May come back with refined tests.
2.3  Temporary problem concerning divisions reported by CMS.
2.4  MC truth handling is documented.
2.5  Marko added some documentation about the usage of units.
     He added a section about namespace usage dd4hep and g4units.
     The specification of the unit namespace is very crucial otherwise
     easily a confusion between dd4hep/TGeo and CLHEP may occur.

4) Round table

   Andre:      Looked in the LCG dev slots. New error from ROOT about pair-parsing.
   Carl:       --
   Frank:      See above in pending items.
   Gabrielle:  --
   Marko:      Work on linker flags pending (PR 751). Work in progress.
               Request to read the sections once the PR is merged.
   Markus:     See pending requests.

5) AOB
   All PR requests with tests passed will be merged.

Next meeting in 2 weeks: 03/12/2020