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Detailed introduction to the LUMI-C environment and architecture

hybrid: Brussels & online

This two-day hybrid course serves as a detailed introduction to the LUMI-C (CPU-only) environment and architecture. The focus of this course is on installing and using software on LUMI. Though it is not a full course for developers on the CPU-only partition, participants will also get some information on porting, executing and optimising applications for the environment.

The course will be jointly conducted by the LUMI HPE Centre of Excellence (HPE CoE) and the LUMI User Support Team (LUST) and is hosted by the Belgian Local Organisation, the FWO and the University of Antwerp.

The course is intended for users with ongoing projects on LUMI, users with project proposals in one of the national or EuroHPC channels, and support staff of local organisations of the LUMI consortium members. Participation will be moderated due to the limited number of participants, but we encourage registrations. This will facilitate the planning of further training events.

The venue for in-person attendance is HOEK 38 in Brussels, Belgium, a recently opened place created by the FWO – Fund for Scientific Research Flanders to foster collaboration and sharing knowledge. See the bottom of this page for more information on the venue. Participants are responsible themselves for all travel bookings.

We will keep a waiting list if registrations exceed the number of planned participants. See the link to the registration at the bottom of this page. The registration deadline is 16 November, 2022 16:00 CET.

Attendance is free of charge. A sandwich lunch will be provided to in-person participants.

Below is a tentative schedule of the course.

23 November (all times CET) 

09:30 Welcome, introduction to the course
09:45 Introduction to the HPE Cray Hardware and Programming Environment
Focus on the HPE Cray EX hardware architecture and software stack.
Tutorial on the Cray module environment and compiler wrapper scripts.
10:55 break (30 minutes)
11:20 First steps to running on Cray EX Hardware
Examples of using the Slurm Batch system, launching jobs on the front end and basic controls for job placement.
Exercises: about 45 minutes
12:40 lunch break (80 minutes)
14:00 Overview of compilers and libraries
An introduction to the compiler suites available. Including examples of how to get additional information about the compilation process. Special attention is given the Cray Compilation Environment (CCE) noting options relevant to porting and performance. CCE classic to Clang transition
Exercises: about 20 minutes
15:30 break (30 minutes)
16:00 Advanced Application Placement
More detailed treatment of Slurm binding technology and OpenMP controls.
Exercises: about 30 minutes
17:00 Open Questions & Answers (participants are encouraged to continue with exercises in case there should be no questions)
17:30 End of first course day


24 November (all times CET)

09:30 Performance and Debugging Tools incl exercises and a break
Includes following content broken up with Exercises/Demos and a break

  • Introduction to perftools
  • Pertfools lite modules
  • Loop work estimates
  • Reveal for performance data display, compiler feedback and automatedscoping
  • Debugging tools at scale
12:30 lunch break (60 minutes)
13:30 Understanding Cray MPI on Slingshot, rank reordering and MPMD launch
High level overview of Cray MPI on Slingshot, useful environment variable controls.
Rank reordering and MPMD application launch.
Exercises: about 20 minutes
14:30 I/O Optimisation — Parallel I/O
Introduction into the structure of the Lustre Parallel file system. Tips for optimising parallel bandwidth for a variety of parallel I/O schemes. Examples of using MPI-IO to improve overall application performance.
Advanced Parallel I/O considerations
Further considerations of parallel I/O and other APIs.
Being nice to Lustre
Consideration of how to avoid certain situations in I/O usage that don’t specifically
relate to data movement.
15:15 break (20 minutes)
15:35 Additional software on LUMI-C

  • Software policy
  • Software environment on LUMI
  • Installing software with EasyBuild (concepts, contributed recipes)
  • Containers for Python, R, VNC (container wrappers)
16:50 LUMI support:

  • LUMI documentation
  • What can we help you with and what not? How to get help, how to write good support requests
  • Some typical/frequent support questions of users on LUMI-C?
17:10 Open Questions & Answers (participants are encouraged to continue with exercises in case there should be no questions)
17:30 End of second course day


Register for the course latest by 16 November, 2022 16:00 CET via this page. We reserve up to 20 in-person places for people traveling to Belgium from abroad, and they will get a quick confirmation on a first come, first serve basis so that they can arrange travel. Other participants will receive confirmation shortly after the deadline. If your plans change, we kindly ask you to cancel your registration as soon as possible (ideally before the registration deadline). The email acknowledging your registration will contain a link to manage it.

Users who don’t have an account on LUMI yet will receive temporary access for the purpose of the course. The compute time allocated to the course should only be used for the purpose of doing the exercises of the course. Any abuse will lead to removal from the allocation for this and future courses.


The course will take place in the Auditorium (third floor) of HOEK 38, Leuvenseweg 38, 1000 Brussels. The location is close to the touristic heart of Brussels.

Access by public transportation: The location is just 500m from the Brussel-Centraal – Bruxelles-Central railway station and hence easy to reach by train. Public transportation (bus, tram and metro) within Brussels is provided by the STIB-MIVB.

Airport information:

  • The closest airport is Brussels International Airport (BRU). One weekdays there are roughly 6 trains/hour between the airport and the Central station. You need to buy your ticket at the airport or at the Central Station for your return trip (or use the NMBS/SNCB app), and keep it with you at all times as the ticket is also needed to pass through the gates at the airport station.
  • Brussels South Charleroi Airport.(CRL) is not in Brussels as the name suggests, but 60km away from Brussels and is popular with budget airlines. There are shuttle busses to the Brussels South station (Bruxelles-Midi) from where regular public transportation should be used to get to the venue, or you can take the bus to the Charleroi Sud station and from there to the Brussels Central station.
  • Schiphol Airport Amsterdam and Paris Charles de Gaulle airport are also options. From both airports there are frequent high-speed trains to Brussels, and there is also a regular train between Schiphol Airport and Brussels that does not require advance reservation.

Hotel information: In general, the bigger hotel groups are safe bets in Brussels. The venue is not far from the tourist area which means that there are a lot of hotels within walking distance, but they tend to be rather pricey. If hotel pricing in Brussels is a problem, another option is one of the more budget-oriented hotels next to the railway station of Leuven. From Leuven, there is a good train connection to the Brussels Central Station, which costs 11.20€ for a return trip.

Please contact LUMI support with further questions.