Tiger Team: tt-nest
NEST on NEMO
The NEST simulator is a standard neuroscience software application (open source) to create and simulate extensive and biologically realistic neural networks. NEST scales from desktops with few cores to supercomputers with hundreds of nodes connected via a high performance network. All tests on the preliminary test cluster (running on legacy hardware with standard InfiniBand) worked without major problems. However, with the transition to the bwForCluster NEMO, NEST would only work reliably when restricting simulations to single nodes.
It became quickly evident that this was not a simple support issue. Resolution of the problem involved NEST users from the Bernstein Center in Freiburg, NEST developers from the Research Center Jülich and the members of the HPC Competence Center ENM.
In the end it was discovered that the root problem was caused by the new Omni-Path hardware in combination with the build environment (i.e. MPI libraries, Kernel). Alongside fixing the problem, weaknesses related to the NEST software deployment strategy where mended and best practices for using NEST on NEMO were established.
First steps where taken to package the rather complex and numerous NEST setup variations into Virtualized Research Environments using Singularity Containers. This will be the topic of a future Tiger Team.
Members of the Tiger Team: Bernstein Center Freiburg, INM-6 (Research Center Jülich), HPC Competence Center ENM