MCNPX On Windows

Running MCNPX with MPI On Windows

You want to run one more processes than the number of cores you have. So on a quad-core system you would use -np 5 and a dual-core system would use -np 3.

On Windows 7 sometimes the DATAPATH environment isn't carried forward to the processes lauched from mpi, so the command lime must include -env DATAPATH C:\mcnpx\data.

All the arguments that follow mcnpx are sent to mcnpx like normal (ie n=, m=, o= etc.). The order of arguments to mpiexec do matter: -np must precede mcnpx.

Examples

• dual-core without setting -env

mpiexec -np 3 mcnpx i=...

• quad-core using -env (Windows 7 only?)

mpiexec -env DATAPATH C:\mcnpx\data -np 5 mcnpx i=...

mpiexec may prompt you for an mpi password, which was entered during setup (and is probably empty). It may also prompt you for an account name and password; the one you use to log in is fine.

Installing MCNPX with MPI On Windows

• Copy MCNPX directory from a working machine
• Install MPICH2
• MPICH2 password should be set to something easy to remember (or empty)
• My Computer->Properties->Advanced->Environment Variables->System Variables
  • Set DATAPATH=C:\MCNPX\DATA
  • Add ;C:\MCNPX\BIN;C:\Program Files\MPICH2\bin to the end path
    • In Windows 7 64-bit, use C:\Program Files (x86)\MPICH2\bin
• Restrict firewall permissions to 127.0.0.1 on mpich