EDM4hep Live Notes
==================
Date: May 12, 2020
Indico: https://indico.cern.ch/event/912622/
This is a document for taking notes during EDM4hep meetings.
Connected: Erica, Jiaheng, Placido, Tao, Andre, Clement, Thomas, Graeme, Frank, Valentin, Gerardo, Weidong Li, Pere
## Introduction and General Points
## Progress and Discussion
* Spack Recipes for LCIO and LCGEO added to k4-spack
## Snowmass Process in the US
* Provide sample for theorists
* Using Delphes?
* NanoAOD with EDM4hep?
* Nano"AOD"
* Something in FCCsw could maybe be adapted
* Many FCChh samples created with Delphes
* Adapt Delphes interface in FCCsw to key4hep
* Delphes plugin to write EDM4hep output
* Need more classes?
* Links to existing plugins etc:
* https://github.com/HEP-FCC/FCCSW/blob/master/Sim/SimDelphesInterface/src/DelphesSaveJets.h
* https://github.com/HEP-FCC/FCCSW/blob/master/Sim/SimDelphesInterface/src/DelphesSaveJets.cpp
* https://github.com/HEP-FCC/FCCSW/blob/master/Sim/SimDelphesInterface/src/DelphesSaveChargedParticles.h
* https://github.com/HEP-FCC/FCCSW/blob/master/Sim/SimDelphesInterface/src/DelphesSaveChargedParticles.cpp
* ...
* Contact Snowmass computing group and discuss possible collaboration
* Discussion [in HSF meeting with convenors](https://indico.cern.ch/event/914479/) (particularly [minutes](https://codimd.web.cern.ch/3-oJL5oBRN6jYKko1KiIXw?view))
* Indico Snowmass Computational Frontier [here](https://indico.fnal.gov/category/1107/)
### Spack installation
* Slides from Valentin
* gcc 8.3.1 (from devtoolset) does not have spack recipe
* Relocation issue, spack error, but works manually
* NB (added after the meeting): Compatibility with devtoolset and ROOT: https://root-forum.cern.ch/t/devtoolset-gcc-toolset-compatibility/38286
* Just for devtoolset 3?
### CMAKE_CXX_STANDARD
* Which standard to use?
* Use the one from ROOT!
* Only support 17?
* Root::TMVA::Cuda requires the use of 14
* Discuss in Key4hep meeting
### Podio
* two small open PRs to be merged (fixes for the issues previously raised)
* Merged
* Build system: CMAKE_CXX_STANDARD
* spack recipe is unnecessarily restrictive (strict dependency that the cxx standard is the same as the one used to build root)
* builds with -std=cxx11 also possible
#### Change Relation Add Method Naming
- https://github.com/AIDASoft/podio/issues/85
- PR: https://github.com/AIDASoft/podio/pull/88
- change "add" to "addTo"
- Merged
### Open Issues
- Tagged v00-10-01
- Run/Event/Collection meta data
- https://github.com/AIDASoft/podio/issues/49
- https://github.com/AIDASoft/podio/pull/71
- Will evolve following tests of EDM4hep in FCCsw, for example
- Store collection metadata once per file, as it should not change
- Event metadata
- Need to store different weights, pile up profile,
- need survey of hh requirements
- Schema Evolution still an open issue
## Schema Evolution
- Version for object descriptions, etc.
- Open issue: https://github.com/AIDASoft/podio/issues/86
## Meta Data
- Work in progress based on LCIO LCParameters (GenericParameters)
- Storing and reading them on demand is tricky, need table of contents to locate correct instance of parameters
- Just do it and make IO performent later?
- Also changes in Readers/Writers/EventStore necessary
## EventStore
- Needs some reworking and definition of interfaces
## LCIOConverters
* Work in progress
## EDM4hep
#### vector member names should be plural
* https://github.com/key4hep/EDM4hep/issues/55
### Associations
- need weight
- Are there in LCIO LCRelation class
- Missing in Association classes
- Should be one to many?
- Generic Association collection?
- See what was done for pLCIO
### Release 1.0
* Need:
* ~~Plugin~~
* ~~Eventheader~~
* Meta Data (Event / Run Parameters)
## AOB
### Issues with Kf4core/EDM4hep
* TODO: Open issue on github with explanation
### Next meeting:
May 26, 2020