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.