Obtain the memory status from all processes (min, max, avg).
Find min, max and average high water mark of the virtual memory usage
across all processes (MPI_COMM_WORLD) on rank 0.
Results are in Megabytes, and the resulting array contains min, max, avg
in this order.
Nodes of different colours represent the following:
Solid arrows point from a procedure to one which it calls. Dashed
arrows point from an interface to procedures which implement that interface.
This could include the module procedures in a generic interface or the
implementation in a submodule of an interface in a parent module.