Instructions and hints on how to run for the OpenMP lab
Where to run
The exercises will be run on PDC's CRAY XC-40 system Beskow:
beskow.pdc.kth.se
How to login
To access PDC's cluster you should use your laptop and the Eduroam or KTH Open wireless networks.
Instructions on how to connect from various operating systems.
More about the environment on Beskow
The Cray automatically loads several modules at login.
- Heimdal - Kerberos commands
- OpenAFS - AFS commands
- SLURM - batch jobs and interactive jobs
Running OpenMP programs on Beskow
First it is necessary to book a node for interactive use:
salloc -A <allocation-name> -N 1 -t 1:0:0
Then the aprun command is used to launch an OpenMP application:
aprun -n 1 -d <number of threads> -cc none ./example.x
In this example we will start one task with 32 threads (there are 32 cores per node on the Beskow nodes).
It is important to use the aprun
command since otherwise the job will run on the Beskow login node.
OpenMP Exercises
The aim of these exercises is to give an introduction to OpenMP programming. All examples are available in both C and Fortran90.
- OpenMP Intro lab:
- Instructions
- Simple hello world program in C and in Fortran
- Calculate pi in C and in Fortran
- Solutions will be made available later during the lab
- OpenMP Advanced Lab:
- Instructions
- In C: shwater2d.c, vtk_export.c and Makefile
- In Fortran: shwater2d.f90, vtk_export.f90 and Makefile
- Solutions will be made available later during the lab