Question

I am broadcasting a pointer to an array

MPI_Bcast(&xd_sim_send, Nooflines_Sim, MPI_FLOAT, root, MPI_COMM_WORLD);

from process 0 and receiving this broadcast from processes other than 0

MPI_Bcast(&xd_sim_recv, Nooflines_Sim, MPI_FLOAT, root, MPI_COMM_WORLD);

I get segmentation fault 11 when I try to read the received value.
Like this

for(i=0; i<Numlines_Sim; i++)
printf("%f\n",xd_sim_recv[i]);fflush(stdout);

What is wrong here, Could you please help me fix it?

Answer 1

If you want to receive the data in a vector other than the one used by root process, then you should do something like this (pseudocode):

if (THIS PROCESS IS ROOT) {
    MPI_Bcast(xd_sim_send, Nooflines_Sim, MPI_FLOAT, root, MPI_COMM_WORLD);
} else {
    MPI_Bcast(xd_sim_recv, Numlines_Sim, MPI_FLOAT, root, MPI_COMM_WORLD);
}

without the &, because the variables xd_sim_send xd_sim_recv are already pointers, that is what MPI_Bcast needs.