GameOfLife

Conway's "Game of Life" Implemented in Modern Fortran with MPI and OpenMP

Features Demonstrated

OO-Fortran

The game_board_type class contains all the necessary data and all operations on these data are type-bound procedures. The overall program should be self- documenting as the basic steps of the algorithm are appropriately named procedures (although the code is somewhat obfuscated by MPI preprocessor guards).

MPI

This code uses the mpi_f08 interface which has a more mondern Fortran style. It also should allow for the use of passing array sections to MPI routines without the cost of unnecessary copies. Support for this style appears to be very recent with some compilers. Some of the MPI features of note that are used include:

• Thread-aware MPI initialization
• Fortran 90 kind equivalent MPI_Datatype creation
• Creation of a Cartesian MPI communicator to allow more optimal rank ordering for the network topology (performance impact unmeasured)
• Non-blocking send/receive calls
• Collective reduction

OpenMP

Some intermediate features of OpenMP are used.

• collapse of parallel do loops for nested DO blocks
• conditional entry into OpenMP regions
• parallel sections for work-sharing of a set number of independent operations; used for MPI send/receive calls when the MPI implementation supports calls from multiple threads (could be performance gain or loss)
• reduction clause in parallel do statement