DD4hep Meeting January23rd, 2025

Present:  A.Tolosa Delgado, M.Frank, T.Madlehner

Apologies: A.Sailer

Link to minutes of previous meeting

Merged PRs

• PR1371: Read edm4hep (Andre)
• PR1374: Do not set or read the color flow for MCParticles from EDM4hep (Juan Carceller)
• PR1376: DD4hepSimulation: pass self to the steeringFile eval (Dimitry Kalinkin)
• PR1380: Restore compatibility with EDM4hep 0.10 (Juan Carceller)
• PR1384: Handle ganged segmentations (Scott Snyder)
                  ==> Allow for implementations of segmentations spanning multiple volumes
                  ==> Use case ?
• PR1385: Fix typo in comment (Scott Snyder)
• PR1386: Fix potential use of dangling temporary (Scott Snyder)
• PR1387: Pseudotrap ref updates. (Markus)

Pending Problems

• ISSUE1199: Persist hepmc vertex status code into output
                        ==> Should we eliminate Geant4EventReaderHepMC
                        ==> Decision: Geant4EventReaderHepMC will be removed
• ISSUE1285:  Memory Consumption of Sensitive Detectors
                        ==> Should be handled as illustrated in PR1288. Intrinsic problem of the Geant4VolumeManager;
• ISSUE1296:  DetectorImp::endDocument() called twice for some geometries?
                        ==> Unsure if it is a problem wrongly configuring multiple xml inputs.
• ISSUE1297:  Possible to dump all available readout elements?
                       ==> Possibly a copy of unsolved ISSUE580 from Valentin about enumerating all sensitive cells.
• ISSUE1319: Problem with regexSensitiveDetector and volume IDs
                       ==> Interesting use case for reg-ex sensitive detectors
                               having a VolumeMgr equivalent.
• ISSUE1320:  Replacing a Handle<Segmentation> which contains a MultiSegmentation with the underlying Segmentation
                       ===> Unclear what he really means. Questions after re-reading, calls like:
  

  Handle<SomeSegmentation> seg = multisegmentation->subSegmentation(cellID);
  or
  Segmentation* seg = multisegmentation->subSegmentation(cellID);
  

• ISSUE1335: Uniform random picking of points on detector surfaces for noise studies
              This problem is linked to #1297 and #580.
• ISSUE1373:  Add GeneratorInfo to EDM4hepReader (Andre)
  PR1371:  Read edm4hep (Andre)
                        ==> Why not closed ?

• ISSUE1379:  Discussion: Evolution of edm4hep and dd4hep enhancement (Markus)

        Pending PRs:(no changes since last meeting):

• PR1240:     Add multithreading support to ddsim
• PR1304:     SurfaceManager: lazily construct surface maps on demand (Leonhard Reichenbach)
• PR1314:     Cylinder segment surface (Armin Ilg)
  
  

        New Pending PRs:

• PR1370:  Feature celeritas integration (Sakib Rahman/EIC)
• PR1377:  Use canonical variables for the installation locations of libraries and binaries (Andriish)
       ==> Idea to have an additional DD4HEP_PLUGIN_PATH and remove dd4hep plugins fdrom the LD_LIBRARY_PATH
• PR1378:  Use standard locations if the LD_LIBRARY_PATH or ROOTSYS are empty (Andriish)

Closed issues and fixed problems

• ISSUE1343:  want to get a parameter into ddsim SDAction at run time (Sarah Eno)
• ISSUE1369: Create EDM4hep reader for DDG4 (Andre)
• ISSUE1372: multiple actions within same subdetector question (Daniel Jeans)
• ISSUE1382:  More useful crash message question (Sarah Eno)

Round Table

Alvaro:      Issue with implementing segmentations. The use case is to have a custom segmentation for
                  specialized sensitive volumes. Required is a user supplied parameter to the readout and
                  the detector element of the sensitive volume. These are already available in the upper level
                  segmentation though. Alvaro will have a look if this information will help to provide a
                  cache object to support such segmentations.
Markus:    Struggeling with the optimization of the Geant4VolumeManager. In principle finished, but now
                  strongly fighting github tests. Getting inconsistent results from dev3 slot.
Thomas:  Reviewed Andres PRs.

AOB

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Next meeting:   February 6th, 2025