MPIruns

Making MPI TRANSP Runs

• MPI version of NUBEAM Monte Carlo model:

  • To run MPI NUBEAM, in your Namelist simply set:

    • nbi_pserve = 1 ! for MPI run with NUBEAM

  • If you use "tr_start" or "xtranspin" the script will detect this setting and ask you how many processors you want.

    • It should be noted that MPI imparts no benefit if the problem size is too small. As a rough guide, we recommend 4000 particles per processor. I.e. for NPTCLS=1000 to 5000 use a standard serial TRANSP run.

    • For NPTCLS=8000 -- Np = 2 For NPTCLS=16000 -- Np = 4 For NPTCLS=32000 -- Np = 8

    • The more processors requested, the longer the queue wait-- users may find that Np = 16 or Np = 8 will be a practical upper limit on the existing PPPL computational cluster.

    • For some runs, MPI may help with smaller particle counts. This will certainly be the case if the low field enhanced FLR model is activated (i.e. if NLBGFLR=.TRUE. as is used in some ST simulations).

• TORIC:

  • under development