Start with :  /usr/bin/mpirun --oversubscribe -display-map -mca btl ^openib  -np num_proc  main.GCC_

/usr/bin/mpirun --oversubscribe -display-map -mca btl ^openib  -np 4 ./main.GCC_
 Data for JOB [34080,1] offset 0 Total slots allocated 4

 ========================   JOB MAP   ========================

 Data for node: LAPTOP-LTDL04HH Num slots: 4    Max slots: 0    Num procs: 4
        Process OMPI jobid: [34080,1] App: 0 Process rank: 0 Bound: UNBOUND
        Process OMPI jobid: [34080,1] App: 0 Process rank: 1 Bound: UNBOUND
        Process OMPI jobid: [34080,1] App: 0 Process rank: 2 Bound: UNBOUND
        Process OMPI jobid: [34080,1] App: 0 Process rank: 3 Bound: UNBOUND

 =============================================================

 Process nr. 0 says, there are 4 processes running.

   0 runs on LAPTOP-LTDL04HH
   1 runs on LAPTOP-LTDL04HH (length: 15 )
   2 runs on LAPTOP-LTDL04HH (length: 15 )
   3 runs on LAPTOP-LTDL04HH (length: 15 )