running embarassingly parallel simulations on a multicore machine using bash loops

  • I need to run a single-processor experiment on some parameters, say N times

  • embarassingly parallel: python scans all these parameters:

    1 for i in range(N):
    2     if experiment[i] is not finished and not locked:
    3         lock(experiment[i])
    4         run(experiment[i])
  • to run this on 8 cores, bash is your friend (may also apply to *sh where * is either z, c, tc, ...)

    for i in {1..8}; do cd /data/work/ && python  & done
  • however, runnning them simultaneously may cause problems if the locking mechanism is not fast enough, so I introduce a random jitter

    for i in {1..8}; do cd /data/work/ && sleep 0.$(( RANDOM%1000 )) ; python  & done