I/O Access Pattern Explanation
N to 1 nonstrided
Each process writes all of its elements contiguously into the file. The file consists of one region per process. Each region contains all elements from that process.
N to 1 strided
Each process writes each element in a single shared "stride" within a single shared file. The file consists of one region per element (not one region per process
as in N-1 non strided). Each region contains "strided" data from each process.
N to N
Each process writes to its own file. Note that N to N is always nonstrided and
that N to 1 nonstrided is same as concatenating all of the N to N files into
a single file.