Use mpiexec rather than mpirun. They are the same, but mpiexec is the newer term.

tools/HPC scripts/gprmax_omp_mpi.sh

@@ -34,4 +34,4 @@ export OMP_NUM_THREADS=8
 
 ### Run gprMax with input file
 cd $HOME/gprMax
-mpirun -np 100 python -m gprMax mymodel.in -n 100 -mpi
+mpiexec -n 100 python -m gprMax mymodel.in -n 100 -mpi