01-hello

Building and running a Kokkos program

Here, the purpose of this exercise is to just understand the simplistic Kokkos hello world program hello.cpp, and the Makefile implementing Kokkos inline build strategy.

Compiling and running

1. If not already done, clone the Kokkos repository in a location of your choice by git clone https://github.com/kokkos/kokkos.git. Set environment variable KOKKOS_PATH to point into that directory, e.g.

export KOKKOS_PATH=/projappl/proj_xxxx/$USER/kokkos

You can also add KOKKOS_PATH=/projappl/proj_xxxx/$USER/kokkos to the beginning of the Makefile

2. Edit the Makefile and pick up CXX, KOKKOS_DEVICES, and KOKKOS_ARCH appropriate to your system. We recommend that you try this exercise both in LUMI and Mahti, and if your laptop has software development tools (e.g. GCC) also there. Build the code by typing make to compile. If you encounter compilation errors, make sure the backend compiler for the desired architecture is available, ie, nvcc for Mahti (use module load cuda) or hipcc for Lumi (use module load rocm).

3. Run on Lumi or Mahti by srun ./executable (add required flags according to the underlying system and user, eg, --account=XXX, --partition=YYY, etc.)

Refs

The exercise code is based on ENCCS material (CC-BY-4.0 license).