Proceedings 2024 ESPResSo meetings

Proceedings of the 2024 ESPResSo meetings

2024-02-21

Bee 2.0 cluster

• Thursday: HPC team meeting to discuss software stack
• Monday: set up the software stack
• Tuesday: online meeting with the company

MultiXscale review highlights

• main objectives of the CoE MultiXscale:
  • EESSI: "app store" for scientific software
  • multiscale simulations with 3 pilot cases: helicopter blades turbulent flow, ultrasound imaging of living tissues, energy storage devices
  • make software pre-exascale ready
  • training on using these software
• ongoing projects for the ICP:
  • improve scaling efficiency of ESPResSo: LJ simulations have only 50% efficiency at 1024 cores
  • teaching people how to use this software: CECAM Flagship Schools 1229 and 1324

Interactive generative modeling

• ZnDraw+SiMGen project in collaboration with Gábor Csányi
• demo available at https://zndraw.icp.uni-stuttgart.de/

LB boundaries bug report

• LB boundaries in the waLBerla version of ESPResSo are broken when using 2 or more MPI ranks
• the LB ghost layer doesn't contain any information about boundaries, so fluid can flow out into the neighboring LB domain, where it gets trapped into the boundary
• more details can be found in the bug report #4859
• the solution will require a ghost update after every call to a node/slice/shape boundary velocity setter function

2024-01-30

Propagation refactoring

• it is now possible to choose the exact equations of motions solved for each particle
• more combinations of integrators and thermostats are allowed
• one can mix different types of virtual sites in the same simulation
• a new Python interface needs to be designed (target for next meeting)

Software and hardware changes

• CUDA 12.0 is now the default everywhere at the ICP
• GTX 980 GPUs are being removed from ICP workstations (GTX 1000 and higher are needed for double-precision atomicAdd)
• Python 3.12 changes the way we use the unittest module (#4852)
• Python virtual environments becomes mandatory for pip install in Ubuntu 24.04
  • user guide needs to reflect that change

2024-01-09

New live visualizer

• ZnDraw bridge is currently being developed for ESPResSo
• supports live visualization in the web browser
• the plan is to re-implement all features available in the ESPResSo OpenGL visualizer

Dropping CUDA 11 support

• CUDA 12 will be the default in Ubuntu 24.04, due April 2024
• CUDA 12 is required for C++20, which makes contributing to ESPResSo significantly easier (#4846)
• compute clusters and supercomputers where ESPResSo is currently used already provide compiler toolchains compatible with CUDA 12