recv_ptr + rank * recv_count * extent,
recv_count, recv_type, rank, tag, comm, &status);
for (i = 1; i < num_procs; i++) {
src = dst = rank ^ i;
recv_ptr + rank * recv_count * extent,
recv_count, recv_type, rank, tag, comm, &status);
for (i = 1; i < num_procs; i++) {
src = dst = rank ^ i;