BLOCK Distribution

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`BLOCK` Distribution

Give equal sized chunks of an array to each processor. For example,

       PROGRAM Chunks
       REAL, DIMENSION(20)       :: A
 !HPF$ PROCESSORS, DIMENSION(4)  :: P
 !HPF$ DISTRIBUTE (BLOCK) ONTO P :: A
   ....

Figure 18: Visualisation of BLOCK Distribution

If an array, A has elements and is mapped onto processors each processor gets a block of (a maximum) of elements. See Figure 18.

Here, the array has 20 elements and this is distributed blockwise onto a four element processor chain. This means that by using the above formula each processor gets a block of 5 elements. The first processor gets the first block, a(1:5), the second gets elements A(6:10) and so on.

Next: CYCLIC Distribution Up: Data Distribution Previous: DISTRIBUTE Directive