On Windows use psutil for probing number of available cores in MPI

(Fix for #2351)

Author: willend

tools/Python/mcrun/mccode.py

@@ -3,6 +3,7 @@
 import sys
 import re
 import shutil
+import psutil
 
 if not os.name == 'nt':
     import shlex as lexer
@@ -441,6 +442,7 @@ def runMPI(self, args, pipe=False, override_mpi=None):
                 LOG.info('Using system default number of mpirun -np processes')
                 if os.name == 'nt':
                     mpi_flags = [''] # msmpi mpiexec.exe does not accept --
+                    mpi_flags = ['-np', str(psutil.cpu_count(logical=False))] # probe number of available (non-logical) CPU's
                 else:
                     mpi_flags = ['--'] # ... whereas openmpi mpirun does.
             elif int(self.options.mpi) >= 1: