EDM4hep Discussion

Tuesday 4 May 2021, 09:00 → 10:01 Europe/Zurich

Zoom

Live Notes

EDM4hep Live Notes
==================

Date: May 4, 2021
Indico: https://indico.cern.ch/event/1035510/
This is a document for taking notes during EDM4hep meetings.

Connected: Tao, Thomas, Andre, Placido, Frank, Birgit, Sanghyun, Valentin, Lorenzo, Clement, Gerri, Joseph, Juraj

Apologies: 

## Introduction and General Points

* vCHEP
    * Received comments from reviewers

* EPS
https://www.eps-hep2021.eu/programme/
Abstract Deadline May 7
Good to submit an abstract for Key4hep
Start from Key4hep vCHEP abstract, expand on podio, update.
Frank will get it started

## Progress and Discussion

* Joseph: 
    * Stack is building with gcc11
    * Some undergraduate level interns looking for a topic to work on, preferably python, about 1 week
        * please open github issues with ideas

## Podio

###  Support for multiple input sources in parallel
* https://github.com/AIDASoft/podio/issues/190
* Please read and maybe comment

### Benchmarking

* Discuss how to integrate with validation in Key4hep

### Issues/PRs

* Fixed width integer types
    * https://github.com/key4hep/EDM4hep/issues/112
    * Needs a bit of adaptation for code generation

* Root performance fixes
    * https://github.com/AIDASoft/podio/pull/180
    * Merged

* Number of fixes [WIP]:
    * https://github.com/AIDASoft/podio/pull/177
    * Not working with ROOT 6.20/04 and older
    * New (stable) pyroot in 6.22 (to be confirmed?)
    * Drop support for older root?

#### Make a tag after all the warnings are fixed

#### Heap-use-after-free

* https://github.com/AIDASoft/podio/issues/174
* Not a problem in frameworks, but if collections used outside of them
* Deep inside the memory management of podio, so not easy to fix
* Happens more often with clang than with gcc, but could be compiler options.
    * Flagged by address-sanitizer
* Maybe requires deep changes. Change for reference counting of object classes.

#### c++ concepts
* BH: add compile time checks for class behaviours: e.g., movable

#### issue w/ ROOT and (vectors of) non-copyable collections
* happens in ROOT 6.22 
* PM: there is a patch available in LCG repository
    * ROOT team is working on a general solution

#### What are the different branches in the root file?
* https://github.com/AIDASoft/podio/issues/169
* Encode more information in the _relation_ branch names?
* Related to use in RDataFrame/RNTupe, directly looking at root file content
* Are branch names an implementation detail?
* backward compatibility "Impossible" (?)

#### Schema Evolution
- https://github.com/AIDASoft/podio/issues/86
- Discussion: https://indico.cern.ch/event/1030566/

#### Multi-Threading

#### "event class" in podio

* Currently being perceived

### PRs
* https://github.com/AIDASoft/podio/pulls

### Meta Data

#### Usage of "metadata" for user defined data
* need to check if current implementation addresses all use cases
* need test use-cases

### EventStore

### Features

* Subset collections?

## LCIOConverters
* https://github.com/key4hep/k4LCIOReader

## EDM4hep
https://github.com/key4hep/EDM4hep/pulls

### MCParticle Endpoint
* https://github.com/key4hep/EDM4hep/issues/113
* Keep podio simple by not allowing getters/setters to access multiple internal states. Use utility functions for this use case, if needed.

### EDM4hep tools
https://github.com/key4hep/EDM4hep-utils

### Issues

## AOB

### Next meeting:

* ~~May 18, 2021~~ vCHEP

### TODO

### New tags for k4SimDelphes
* Updated podio
* Updated Delphes version
    * Update spack fork and main spack

 

09:00 → 09:05 Introduction

Speakers: Andre Sailer (CERN), Frank-Dieter Gaede (Deutsches Elektronen-Synchrotron (DE))

EDM4hep Github

Podio Github

10:00 → 10:01 Discussion

Speaker: Dr All