1This directory contains a few example programs.
2
3Each program takes the filename as a command-line argument
4"-fname filename".
5
6If you are using "mpirun" to run an MPI program, you can run the
7program "simple" with two processes as follows:
8   mpirun -np 2 simple -fname test
9
10
11simple.c: Each process creates its own file, writes to it, reads it
12          back, and checks the data read.
13
14psimple.c: Same as simple.c but uses the PMPI versions of all MPI routines
15
16error.c: Tests if error messages are printed correctly
17
18status.c: Tests if the status object is filled correctly by I/O functions
19
20perf.c: A simple read and write performance test. Each process writes
21        4Mbytes to a file at a location determined by its rank and
22        reads it back. For a different access size, change the value
23        of SIZE in the code. The bandwidth is reported for two cases:
24        (1) without including MPI_File_sync and (2) including
25        MPI_File_sync.
26
27async.c: This program is the same as simple.c, except that it uses
28        asynchronous I/O.
29
30coll_test.c: This program tests the use of collective I/O. It writes
31        a 3D block-distributed array to a file corresponding to the
32        global array in row-major (C) order, reads it back, and checks
33        that the data read is correct. The global array size has been
34        set to 32^3. If you are running it on NFS, which is very slow,
35        you may want to reduce that size to 16^3.
36
37coll_perf.c: Measures the I/O bandwidth for writing/reading a 3D
38      block-distributed array to a file corresponding to the global array
39      in row-major (C) order. The global array size has been
40      set to 128^3. If you are running it on NFS, which is very slow,
41      you may want to reduce that size to 16^3.
42
43misc.c: Tests various miscellaneous MPI-IO functions
44
45atomicity.c: Tests whether atomicity semantics are satisfied for
46      overlapping accesses in atomic mode. The probability of detecting
47      errors is higher if you run it on 8 or more processes.
48
49large_file.c: Tests access to large files. Writes a 4-Gbyte file and
50      reads it back. Run it only on one process and on a file system
51      on which ROMIO supports large files.
52
53large_array.c: Tests writing and reading a 4-Gbyte distributed array using
54      the distributed array datatype constructor. Works only on file
55      systems that support 64-bit file sizes and MPI implementations
56      that support 64-bit MPI_Aint.
57
58file_info.c: Tests the setting and retrieval of hints via
59      MPI_File_set_info and MPI_File_get_info
60
61excl.c: Tests MPI_File_open with MPI_MODE_EXCL
62
63noncontig.c: Tests noncontiguous accesses in memory and file using
64             independent I/O. Run it on two processes only.
65
66noncontig_coll.c: Same as noncontig.c, but uses collective I/O
67
68noncontig_coll2.c: Same as noncontig_coll.c, but exercises the
69             cb_config_list hint and aggregation handling more.
70
71i_noncontig.c: Same as noncontig.c, but uses nonblocking I/O
72
73shared_fp.c: Tests the shared file pointer functions
74
75split_coll.c: Tests the split collective I/O functions
76
77fperf.f: Fortran version of perf.c
78
79fcoll_test.f: Fortran version of coll_test.c
80
81pfcoll_test.f: Same as fcoll_test.f but uses the PMPI versions of
82               all MPI routines
83
84fmisc.f: Fortran version of misc.c
85