mpi-alltoall-example.c

#include "mpi.h"

int           sendcount, recvcount;
void          *sendbuf, *recvbuf;
MPI_Datatype  sendtype, recvtype;
MPI_Comm      comm;
...
MPI_Alltoall(sendbuf, sendcount, sendtype, 
             recvbuf, recvcount, recvtype, comm);
...