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HSF Weekly Meeting #178, 23 January, 2020 - Lund Workshop Planning Meeting

Present: Graeme Stewart, Pere Mato, Agnieszka Dziurda, Philippe Canal, Sam Meehan, Stefan Roiser, TJ Khoo, Andrea Valassi, Serhan Mete, Witek Pokorski, Paul Laycock, Mason Proffitt, Ben Morgan, Markus Schulz, Liz Sexton-Kennedy, David Lange, Josh McFayden, Kyle Knoepfel, Mark Neubauer, Efe Yazgan, Daniel Elvira, Caterina Doglioni, Chris Jones

Organising team for HSF are: Graeme, Heather, David and Michel - please get in touch with any suggestions you have.

Plenary

• Opening session on Monday afternoon and closing session on Friday will be in plenary
• For Monday we foresee some overview talks to set the scene
  • We have specifically reached out to some non-HEP communities, e.g. ESS, Dark Matter, Astroparticle, ESCAPE
  • Good time to give an HSF review talk, for new people to the software and computing area
  • Would it be useful to have some cross-cutting technology items, e.g. compute accelerators or networking…?
• Our WLCG colleagues have mooted a plenary session on “portability and sustainability of workflows”. Maybe 0.5 days. Proposed to cover aspects around 1) software/infrastructure sustainability; and 2) the process for supporting “new” architectures (be it HPC or otherwise) on the grid. Both potentially broad areas. Could eat 0.5 days from the parallel session blocks.
  • Ben - could overlap with software and tools area (packaging)?
  • Liz - maybe less overlap? Is Geant4 suffering from “the tragedy of the commons”? Everyone wants it, but wants others to pay for it… HSF was created to address this
    • Geant is a priority, but we lack a coherent voice
    • Storage technologies are evolving
  • Andrea - suggest more plenary? That’s the point of the joint workshop
    • Plenary talk from each WG to increase awareness
      • Concern this would be too much like a general round-table of status reports without much discussion?
      • Fold a little piece from each WG into an HSF overview?
    • HL-LHC review “summary” (this was foreseen)
  • Paul - likes the idea of crossover talks, following the themes above
  • Stefan - cross cutting topics could be things like vectorisation on the grid
    • Heterogeneous resources… (and HPCs) - roadmap to GPU workloads?
      • How do you manage them? What software do you run in them?
  • Andrea: definitely HPCs could be an interesting topic for a cross-over session, with both computing and software people. As an example, we had HPC meetings with computing people mainly discussing computing integration issues (storage, workload, network, O/S…), while those specific issues like Summit have mainly GPU computing, and we essentially have no GPU workloads ready to run in production at that scale. It would be useful for instance from the reconstruction/trigger WG to know how much of their GPU work is online farm specific, and how much can be exploited on HPCs.

Parallel

• Tuesday, Wednesday and Thursday will probably (all) be parallel HSF
  • We could have 2 items ongoing (there are 3 rooms in total), but will need negotiations with our computing colleagues
• The DOMA/Analysis workshop pre-CHEP was a success, with the interactive sessions appreciated
• Should we try to do something along the same lines here?
• e.g. Reconstruction and Simulation are the other major resource impacting areas
  • This would mean dedicating a day to each of these
  • How best to get everyone involved in discussions and have useful outcomes?
    • New ideas
    • R&D
    • Shared projects
  • The large room is amenable to splitting into smaller groups
• If we do this then only one more (or just 0.5) day left (unless not using Monday morning is reconsidered)
  • That means we cannot cover all topics!
• Ideas and thoughts for other WGs:
  • Generators is a centre of expertise in Lund, can we take advantage of that and organise something significant, building on the Nov 2018 workshop
  • Software Tools and Packaging is an active group, with widespread impact, so a session makes sense
  • Frameworks is a new group, so a first session in the workshop will help bootstrap and define directions
  • Training - could have a session, but what would need discussed in this forum that would drive outcomes?
  • Analysis had a session in Adelaide and we felt the next event needed to be at CERN to get the coal-face analysts
  • PyHEP organised the UK workshop and are busy with the SciPy 2020 event
  • [Caterina] Pro domo mea, literally: I have started a “local” group called REALTIME, including people from other faculties (psychology/law/astronomy/engineering), who are interested in real-time data acquisition / analysis. Info in English here: https://realtime.blogg.lu.se/hej-varlden/ I talked to them on Monday and they were keen for a mingle, but we could also do something totally out there and have a trigger&reco discussion session that includes them (not sure it’d be of program-wide interest though).
• If a WG does not have a dedicated session, we could have WG reports that cover the main activities and directions (as full plenary or an HSF “summary” session)

Working Group Thoughts and Feedback

• Assume that we’re looking at 4 sessions in a whole day, each session being ~90 minutes long.
• Let us know how many sessions your group would use.
  • Or if you’d like an overview talk instead
• Do you want to have some group interaction during your session (which was really a success in Adelaide); this helps a lot getting everyone discussing and can be very fruitful.
  • Bear in mind this needs to have enough time dedicated to it.

Reconstruction and Software Triggers

See above for an interdisciplinary thought from Caterina. copied from above:

• [Caterina] Pro domo mea, literally: I have started a “local” group called REALTIME, including people from other faculties (psychology/law/astronomy/engineering), who are interested in real-time data acquisition / analysis. Info in English here: https://realtime.blogg.lu.se/hej-varlden/ I talked to them on Monday and they were keen for a mingle, but we could also do something totally out there and have a trigger\&reco discussion session that includes them (not sure it’d be of program-wide interest though).
• Graeme - Better not to have this as lunch, which would limit participation, but really get input from them in ~1-2 session slot (tools, licensing are topics in which we have expertise)
• Need to have a chat among ourselves before deciding, but it could be a good idea to have a longer topical discussion on accelerators for trigger and reconstruction (shared with frameworks?) since we keep getting interest from people wanting to give talks and here we could have a longer session.
• One interesting thing would be to have a talk for non-standard reconstruction techniques for long lived particles. The issue here is that tracking is generally CPU-expensive, and one risks missing those signatures at the trigger level because one can’t reconstruct the features fast enough. Various grapevines tell me (Caterina) that this is a hot topic in both ATLAS and CMS, but I haven’t talked to LHCb/ALICE yet.
• Focus on this for the HEP Reco session, also brings in physics analysis people
• Interesting CMS work (we think) on LLPs

Accelerator crossover with simulation, generators and frameworks… identify generic work where possible.

Detector Simulation

We think that one full day of parallel session on simulation is a very good idea, taking into account how critical simulation CPU performance and physics precision is becoming. We would probably like to have 4 different sessions along the general axis of improvements/modernization of Geant4, fast simulation and new hardware technologies (accelerators, HPC, etc). Physics precision is also a very important topic that should not be ignored, but this should in principle be covered by the LPCC workshop that we are planning to have in the second half of 2020. We would be very pleased to have more Geant4 community involved. We would also be interested to hear about successful attempts of porting simulation software to accelerators from other communities (outside HEP).

Data Analysis

Topics for the start of year are Analysis languages and Analysis meets DOMA, our first WG meeting is tomorrow :) Cross-over topics in other WG parallels might be of interest, seeing as we needn’t have a dedicated session:

• Analysis languages crossover with frameworks?
• Another crossover with frameworks that came out of the Adelaide workshop was how to integrate industry standard ML toolkits with frameworks
• Analysis meets DOMA would make use of WLCG but we hogged the Adelaide agenda.
• Real-time analysis and the other Reco topics esp if physics reps will come
• Training would also be natural.
• ML/GPU +1

Frameworks

Not certain who will be at Lund yet from FNAL. Cross cutting topics would be really interesting - scheduling accelerator jobs, portability issues. How to make use of an HPC as an application. Exploring different frameworks and examining complications… once finished

PyHEP

• We do not request a parallel session.
• We kindly request a plenary report on WG activities, if possible within the time budget.

Tools and Packaging

Serhan : Will probably be able to discuss tomorrow. Last two HOW workshops, we had 1h30min parallel sessions with approximately 50% talk

• 50% discussions. Overall, I think this is a balanced approach. We might have three or so talks (15’ + 15’). The usual suspects:
  • Build systems + packaging + software distribution
  • Profiling/monitoring tools (maybe focus a bit on accelerators)
  • Static analyzers (linters etc.)
  • IDEs (and perhaps integrating some of the above tools therein) - cross over with training!

Training

Sam M. : I’m sorry that I could not attend the meeting [ref. Coordination meeting 16 Jan]. I do think that having a session would be good and I think that if we want to consider outcomes, then having the critical mass of people to brainstorm what types of bootcamps we need would be helpful. We can then discuss this with the experience of the last year in mind [specifically how we held the workshops] and that would provide the concrete list of events that we need to plan in the coming year - spanning ~July 2020 - July 2021. Caterina: another “crazy host” idea: would you be willing (and would there be interest) to organize a mini-bootcamp before/after the workshop? Students may be encouraged to fly on Sunday night and in the morning we have the rooms. In Lund we have huge interest from all faculties on our Jupyter course and if we do something generic we can “expand our horizons”. → Caterina will follow up with Sam towards the end of next week.

Generators

We have a generator meeting at 4pm after this one, where we will also discuss the LUnd workshop more in detail. Lund is sort of the ‘home’ of MC generators and there are people there working in Pythia, MadGraph, Herwig, possibly more. It would certainly be nice to organise one parallel session to meet and engage with some of those experts, who are not normally involved in our WG activities. We have not yet made contacts but will do soon. So in principle we request one parallel slot (90 minutes?). We could have a plenary talk if people find this useful [Andrea more generally suggested that each WG gives one, but some people feel otherwise]

AOB

We are asked for a letter of collaboration for an AI Institute proposal going to the HSF, “AI Institute: Community Laboratory for AI Research at the Intersection with Physics (CLARIPHY)” (from Pete Elmer). The HSF’s collaboration would be in training and workshops: https://docs.google.com/document/d/13YHqtL3UI0QV5KQ8fUQ0ab0jiDzs7Nw089lbzjW-rS4/edit?usp=sharing Can we approve this? Comments until tomorrow morning CERN time as the proposal deadline is very close. We would like a ~1 page summary so that we can check we approve the idea. Mark: there will likely be other asks for this call. Graeme: we can sign off without a meeting as long as the letter and project description are circulated.

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