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Next: Explicit Parallel I/O Up: Hints Previous: FILEMAP Directive

File mapping

ALIGN and DISTRIBUTE statements are used to map FILEMAPs onto nodes. The syntax is identical to the syntax for processor mappings, with one restriction: Block distributions cannot be used for the last (infinite) dimension of the filemap.

For example:

!HPF DISTRIBUTE F1(*,BLOCK,CYCLIC(2)) ONTO D1 Assume that F1, F2 are the filemaps and D1, D2 are the node arrangements from the previous examples.

The first distribute statement specifies the following mapping for successive records of a file associated with F2 or F3.

D2(1,1)         D2(1,2)

1 (1,1,1)       3 (1,2,1)
5 (1,1,2)       7 (1,2,2)
.               .
.               .
.               .



D2(2,1)          D2(2,2)

2 (2,1,1)        4 (2,2,1)
6 (2,1,2)        8 (2,2,2)
.                .
.                .

The second distribute statement specifies the following mapping for successive records of a file associated with F1.

D1(1,1)           D1(1,2)          D1(1,3)            D1(1,4)

 1 (1,1,1)       17                33                 49
 2 (2,1,1)       .                 .                  .
 3 (1,2,1)       .                 .                  .
 4 (2,2,1)       20                36                 52
 9 (1,1,2)       25                41                 57
10 (2,1,2)       .                 .                  .
11 (1,2,2)                         .                  .
12 (2,2,2)       28                44                 60
65               81                97                113
.                .                 .                  .
.                .                 .                  .



D1(2,1)            D1(2,2)         D1(2,3)            D1(2,4)

 5 (1,3,1)         21              37                 53
 6 (2,3,1)         .               .                  .
 7 (1,4,1)         .               .                  .
 8 (2,4,1)         24              40                 56
13 (1,3,2)         29              45                 61
14 (2,3,2)         .               .                  .
15 (1,4,2)         .               .                  .
16 (2,4,2)         32              48                 64
69                 85             101                117
.                  .               .                  .
.                  .               .                  .