Overview
Neko is a portable framework for high-order spectral element flow simulations. Written in modern Fortran, Neko adopts an object-oriented approach, allowing multi-tier abstractions of the solver stack and facilitating various hardware backends ranging from general-purpose processors, CUDA and HIP enabled accelerators to SX-Aurora vector processors. Neko has its roots in the spectral element code Nek5000 from UChicago/ANL, from where many of the namings, code structure and numerical methods are adopted.
For more information, please visit https://neko.cfd.
Note: The page may be changed until the competition stats, maybe sure to follow up until the opening ceremony.
Building and Running example
Download Neko v0.6.1, https://github.com/ExtremeFLOW/neko/archive/refs/tags/v0.6.1.tar.gz.
Sample build script:
tar xfp v0.6.1.tar.gz cd neko-0.6.1/ # Load intel compilers and mpi ./regen.sh ./configure CC=mpiicc FC=mpiifort --prefix=<path> make make install
Note: Intel MPI is recommended, OpenMPI may not be stable, but you are welcome to try.
Sample run script:
# Load intel compilers and mpi mpirun -np 128 -genv I_MPI_PIN on neko tgv.case
Sample output:
_ __ ____ __ __ ____ / |/ / / __/ / //_/ / __ \ / / / _/ / ,< / /_/ / /_/|_/ /___/ /_/|_| \____/ (version: 0.6.1) (build: 2023-09-14 on x86_64-pc-linux-gnu using intel) -------Job Information-------- Start time: 18:44 / 2023-09-18 Running on: 128 MPI ranks CPU type : Intel(R) Xeon(R) Platinum 8280 CPU @ 2.70GHz Bcknd type: CPU Real type : double precision -------------Case------------- Reading case file tgv.case ... --------Postprocessing-------- --------Writer output--------- File name: field.fld Output number: 2 Writing at time: 2.000500 Output time (s): 2.501281 Normal end.
GPU support:
To compile Neko with GPU support, please follow the generic CUDA instructions at https://github.com/ExtremeFLOW/neko/discussions/540
Note: A Neko installation can only support one backend. Thus, to run both CPU and GPU experiments, two different builds and installations are necessary.
Input file:
Tasks & Submissions
Run Neko with the given input on 4 CPU nodes and submit the results to the team’s folder (standard output,
field0.f00000
,field0.f00001
andfield0.nek5000
)Run Neko with the given input on 4 GPUs (V100) and submit the results to the team’s folder (see instructions for GPU support above, and the additional information provided with the input file)
Run IPM profile or any other MPI profile on 4 nodes, and find the 3 most used MPI calls, show your work in the team interview.
Create a visualization short video with Paraview and show it on your team interview
Change
nsamples
to e.g. 100 intgv_Re1600.case
Download all
field0.*
files to a machine with Paraview (e.g. your laptop)Open
field0.nek5000
in Paraview, don’t forget to select all “Point Arrays” before pressing “Apply”Try various filters and representations, for example, iso-surfaces, glyphs or volume rendering
The flow field will show more interesting features if the simulation is allowed to run longer (controlled by
T_end
in the case file).
To save the final animation, follow the instructions at https://docs.paraview.org/en/latest/UsersGuide/savingResults.html#saving-animation
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