EDM4hep Discussion



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?


* 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



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