General idea

Roland is a Linux computation server on which a scheduler (sbash) controls the script under execution. The scheduler distributes the computation among up to 64 threads depending on the instructions in the bash file.

Prerequisites:

If you want to use this server, you must have received express approbation from Maxime Jacquet. Proceeding otherwise will unleash a mess nobody wants to have to contend with.
You may only run computations on Roland if you have checked beforehand that they succeed on your computer, including the multithreading. Failure to comply will cause harm.

Bash file

Execution of the code on Roland is controlled by a bash script (a recipe whose instructions are executed by the console/shell). A minimal working version of the bash script features the following:

    #!/bin/bash
    #SBATCH -c 63
    #SBATCH --ntasks 1
    #SBATCH --mem=50000M
    #SBATCH --job-name=polariton

which controls the number of threads (-c) used, the number of tasks to perform, the allocated physical memory (how much space the data may fill) and a job-name.

If you use the Julia language, you need to set and export the thread variable bash export JULIA_NUM_THREADS=64 for your programme to use.

Finally, you must instruct the shell to run your Julia programme:

bash julia simulation_roland_v0.jl

Note this assumes your Julia code is in the same directory as your bash file.

Useful commands

bash sinfo provides info on the use mode of Roland (eg the available max_N_hours) bash squeue provides info on current server usage by users bash htop provides info on current use (threads, tasks)

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