24 Aug
2016
24 Aug
'16
12:28 p.m.
Hello, This may be a silly question, but the reason I'm asking is to obtain a fairly definitive answer. Basically, does MPICH have data structures which are of size: 1) O(N) 2) O(N^2) Where N is the size of MPI_COMM_WORLD ? My initial guess would be no, because there exist machines (Mira) for which it is not possible to store N^2 bytes, and even N bytes becomes an issue. I understand there are MPI functions (MPI_alltoall) one can call that by definition will require at least O(N) memory, but supposing one does not use these, would the internal MPICH systems still have this memory complexity ? Thank you for looking at this anyway