rank = smpi_comm_rank(comm);
num_procs = smpi_comm_size(comm);
+
+ if((num_procs&(num_procs-1)))
+ THROWF(arg_error,0, "alltoall pair algorithm can't be used with non power of two number of processes ! ");
+
send_chunk = smpi_datatype_get_extent(send_type);
recv_chunk = smpi_datatype_get_extent(recv_type);