EDM4hep Discussion

Tuesday 25 Nov 2025, 09:00 → 10:00 Europe/Zurich

Zoom

Live Notes

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

Date: Nov 25, 2025
Indico: https://indico.cern.ch/event/1615736/

Connected: Andre, Juraj, Juan, Pere, Thomas, Tao, Brieuc

Apologies:

### Upcoming workshops / conferences
https://github.com/orgs/key4hep/projects/4/views/1

## Progress and discussion

## Podio
* https://github.com/AIDASoft/podio/issues
* https://github.com/AIDASoft/podio/pulls
* https://github.com/orgs/AIDASoft/projects/2/views/1

 
### Merged PRs

- Don't use- move to tools and rename podio_test_hashes [#881](https://github.com/AIDASoft/podio/pull/881)
- Add information about file size and compression in podio-dump [#878](https://github.com/AIDASoft/podio/pull/878)
- Make `Frame::get<T>` throw on non-existing collections instead of returning an empty collection [#868](https://github.com/AIDASoft/podio/pull/868)
- Make sure to read only necessary collections [#880](https://github.com/AIDASoft/podio/pull/880)
- Skip unreadable collections instead of either crashing or skipping entire frames [#863](https://github.com/AIDASoft/podio/pull/863)
- Add a workflow that builds all the way to EDM4eic [#872](https://github.com/AIDASoft/podio/pull/872)

### Fix memory leak in the TTree Reader
* https://github.com/AIDASoft/podio/pull/882
* https://github.com/AIDASoft/podio/issues/883
* Long standing, also visible, see e.g. plots from Juraj (RDataSource benchmarking)

### Change the grammar of the schema evolution files
* https://github.com/AIDASoft/podio/pull/845
* No users in EDM4hep & EDM4eic
* Plan to merge this soon
    * Will be necessary for https://github.com/key4hep/EDM4hep/pull/465

### Add the possibility to extract collections from a Frame
* https://github.com/AIDASoft/podio/pull/856
* Feature request from Acts (Paul)
    * Not sure if the actual problem they have is not better solved with an appropriate DD4hep ParticleHandler
    * Aware of the existing functionality in podio to do the remapping (e.g. `clone`-ing collections and manually re-setting relations)?
    * could also use the type lists that we generate to do some variadic template things?
* Might still be useful as an "expert feature"?
    * Could be useful for RDataFrame for mutating a collection(?)
* **How does this interact with the policies above?**
    
## EDM4hep
* https://github.com/key4hep/EDM4hep/pulls
* https://github.com/key4hep/EDM4hep/issues
* https://github.com/orgs/key4hep/projects/5 

### Merged PRs
- Hide CollectionBuffers::recast depending on podio version [#463](https://github.com/key4hep/EDM4hep/pull/463)
    * Necessary to work after https://github.com/AIDASoft/podio/pull/882

### Consistently name intrinsic Cluster angles
* https://github.com/key4hep/EDM4hep/pull/465
* Test case for schema evolution for renaming of variables
* [ ] Check usage

### Store old schema version YAML files explicitly
* https://github.com/key4hep/EDM4hep/pull/464
* Necessary in the future for schema evolution (podio needs to have access to all versions from which schema evolution should be possible)

### EDM4eic Jet proposal 
* https://github.com/eic/EDM4eic/pull/118
* [slides at ePIC S&C meeting](https://indico.bnl.gov/event/30539/contributions/116587/attachments/66199/113656/JetDatatypeProposal_epicWeeklySCMeeting.d12m11y2025.v0.pdf)
* Asked for slot at next Key4hep meeting with US friendly time slot for discussion
    * Dec 2
    
### `type` field in `Quantity`
* How to use/
    * Should we define constants e.g. in `RecDQdx`? -> Yes
* Alignment issue with 16 bit integer?
    * Make it 32 bit to not waste the padding
    * [ ] Check if schema evolution accepts that

## Converter & MarlinWrapper

## AoB

## Next meeting:
* Dec 9, 09:00

09:00 → 09:05 Introduction

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

EDM4hep Github

Podio Github

09:50 → 09:51 Discussion

Speaker: Dr All