ROOT Meeting 26th June 2023

1. News

• new summer students  — welcome everyone! 
  • Victoria — project storage layer in RNTuples with Jacob and Javi
  • Silia — RDataFrame with Vincenzo 
  • Uri — SOFIE with Lorenzo
  • Stefan — Graph NN with Lorenzo 
  • Daniel W. — benchmark of the statistical tools with Jonas
  • Daniel A. — high performance computing with Jonas 
• Axel - vacation starting next Tuesday (July 4th)
• summer student course on ROOT — Wednesday the 28th July, or July 27th 
• PPP meeting is back! (this week - Thursday, 29th June, 4pm, email will be sent out soon, chairs: Vincenzo and Marta) 
  • topic for this week: new feature in distributed RDataFrame by Vincenzo 
  • we want it to become more regular - new developments, new design proposals, benchmarks etc.

2. Shift handover

• Olivier —> Marta 
• nothing special happened last week
• forum ok, report on nightlies in MM, PRs and issues are assigned
• MacOS beta - brew installed - Olivier will look into this 
• for the future reference: tag Axel for cling related questions

3. Meetings from last week 

• I/O 
  • status updates — xrootd (remote data access) —> software penalises MT application over multi-process applications — fix from xrootd developers, temporary fix 
• TMVA
  • Lorenzo not here
• RooFit
  • nothing to report 
• Planning / Godparents /...
  • open bug reports from LHCb —> no reproducers available 
  • CMS —> ARM CPUs from the UK grids - new MT issues in the I/O, new ARM machine to reproduce the issues maybe needed? (Philipe and Jonas H. should look into this)
• LIM
  • nothing to report

4. Special Presentation —> Making web canvas the default [Sergey] 

Discussion/Q&A: 

• Jonas R. 
  • 0.7s to generate image - what was the time before? —> 1000s of images per second — degradation of the performance now if they do it sequentially in the web , so needs special API for these cases (shouldn’t be a big issue)
• Axel: 
  • chances not making it default for batch but only for interactive, are canvases different on screen and in pdf? — not much difference, unless you count every single pixel - then that may be different, but generally not a big difference 
  • web canvas vs. old canvas (I tweak things in web canvas, then I run in batch, then I want a pdf, will there be any differences) —> there should be no new features in web canvas that cannot be represented by the old TCanvas 
  • do they offer the same set of features? — old canvas — two new classes, small new features can be done in parallel, for the moment should not be any differences
  • complex experiment examples — 500 line per macro — how close are these between the web canvas and TCanvas? — mainly the same, maybe some latex rendering would differ,  but fill style, markers etc — the same
  • TBrowser vs RBrowser (ROOT 7 browser, it will always use web canvas) 
  • when RBrowser was only in master (and not in release) — any feedback there? — not really, feedback after release, 
    • web default for interactive, TCanvas default for batch —> in master
    • web for batch — new API needs to be discussed in the future
• Vincenzo: 
  • which features can be switched off and on and when?
  • TWebCanvas — why this name? — implementation — TCanvasImp - implementation of the canvas, WebCanvas - class derived from TCanvasImp, user shouldn’t worry, automatically done with “root --web”
  • for ROOT 7 — how much will have to be reworked, there is different development there - RCanvas 
  • re-use as much as possible from this implementation into the RCanvas
  • feature compatibility: how many use cases would be broken by using the web canvas? - shouldn’t be worse than usual 
• Jacob 
  • save file from web canvas — file dialog in web GUI - file saved on the remote folder on lxplus for example 
  • make it available for GUI power users — testers — activate with  “—web” option

Conclusion: 

• try in master but not in the release 

Action Item: 

• Sergey — mention this on the forum/announce/blog post — so people test it 

5. Roundtable - skipped for today - tomorrow morning at 9am (27.06.23) on zoom

Roundtable 27.06.23

Olivier 

• on shift last week - a lot of work on the forum 
• now: work on mac mini 

Bertrand

• windows problem with interpreter and visual studio
• lvlm patch 
• will work on cmake 

Axel

• work on CI 
• cling and clang issues 
• converge on open PR’s 
• this week: help LHCb - their datataking problem 
• patch release once back from vacation — first half of August 

Vincenzo 

• last week: concluded bunch of PRs
• work on RNtuple data with Grand Analysis Challenge
• preparing Summer Student projects and courses (new repo)
• met with a power user from Spain - detector physics experiments framework based on ROOT, maybe use RDataFrame there, they also want to organise school, maybe they will invite us too 

Florine 

• last week: support for the standard sets, using collection proxies — it almost works now, ready for the reviews soon 
• start work on support for std::maps 

Jolly

• last week: ported CUDA histograming to SYCL 
• will look into GPU versions of de-compression 

Jonas

• last week: patches to lvlm and clang 
• yesterday: got rid of one of ugly cling patches 

Marta

• summer student course preparation 
• work on progress bar
• discussed with Enrico and Vincenzo about the physics side of the refactored Grand Analysis Challenge