mpich runtime error

[chaochinyang (Chao-Chin Yang)]

I can install mpich normally on my M2 Ultra Mac Pro with Ventura 13.6.3 (22G436)

sudo port install mpich

and compile a simple hello world from ​MPI Tutorial.

#include <mpi.h>
#include <stdio.h>

int main(int argc, char** argv) {
    // Initialize the MPI environment
    MPI_Init(NULL, NULL);

    // Get the number of processes
    int world_size;
    MPI_Comm_size(MPI_COMM_WORLD, &world_size);

    // Get the rank of the process
    int world_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);

    // Get the name of the processor
    char processor_name[MPI_MAX_PROCESSOR_NAME];
    int name_len;
    MPI_Get_processor_name(processor_name, &name_len);

    // Print off a hello world message
    printf("Hello world from processor %s, rank %d out of %d processors\n",
           processor_name, world_rank, world_size);

    // Finalize the MPI environment.
    MPI_Finalize();
}

However, when I run the executable

mpiexec -n 2 ./a.out

I cannot even MPI_Init the run:

Fatal error in internal_Init: Other MPI error, error stack:
internal_Init(66)..................: MPI_Init(argc=0x0, argv=0x0) failed
MPII_Init_thread(234)..............: 
MPID_Init(67)......................: 
init_world(171)....................: channel initialization failed
MPIDI_CH3_Init(84).................: 
MPID_nem_init(314).................: 
MPID_nem_tcp_init(175).............: 
MPID_nem_tcp_get_business_card(397): 
GetSockInterfaceAddr(370)..........: gethostbyname failed, UA-9RH32PX (errno 0)

[eborisch (Eric A. Borisch)]

Does mpiexec -host localhost -n 2 ./a.out work?