1 | The example uses three idealized (not present in real message passing system) primitives |
2 | Message Passing Shift to right MPSHIFT (+1, SOURCE, DEST) |
3 | Sends 1 word in location SOURCE to processor on the right |
4 | Receives word in location DEST from the processor on the left |
5 | SOURCE and DEST are locations -- if set to "DUMMY", then no information is to be sent or received |
6 | Message Passing Shift to left MPSHIFT (-1, SOURCE, DEST) |
7 | Sends 1 word in SOURCE to processor on the left |
8 | Receives word in DEST from processor on the right |
9 | GLOBALMAX (TEST) |
10 | takes TEST from all processors |
11 | forms TESTMAX = maximum value of TEST over all processors |
12 | replaces TEST by TESTMAX in all processors |