2.4. How to change the executable file

The PHITS executables are all stored in the phits/bin folder for Windows, Mac, and Linux, and include not only a single mode, but also parallel computing and debugging. These executables can be used differently by putting the command before the first section of the input file.

To execute PHITS via parallel computing using MPI or OpenMP. The shared-memory parallel computing using OpenMP can be executed by adding

$OMP=N

(N is the number of CPU cores to be used) before the first section in the PHITS input file. If N=0, all cores in the computer are used. If N=1, the parallel computing is not used. From version 2.73, the executable file of the OpenMP version coming along with the PHITS package is available only for 64-bit Windows systems. The MPI version of PHITS can be also executed by added

$MPI=M

in the same manner as OpenMP, but the installation of a MPI protocol (Intel MPI for Windows and Linux) is required. Please see Section 11.1.1 in more detail.

The executable files of PHITS in the debug mode, which checks for memory violations and uninitialized variables, can be set when

$DBG=1

is written before the 1st section of the input file. When access violation or Segmentation fault are occurred during the execution of PHITS, or when you find infinite loops and abnormal termination of calculations, please append $DBG=1 to the first line of the input file that If you get any error messages, please send the messages to PHITS office, together with the information on your machine environment.