Examples of Good Distributions

Given the following assignments:

  A(2:99) = (A(:98)+A(3:))/2 ! neighbour calculations
  B(22:56)= 4.0*ATAN(1.0)    ! section of B calculated
  C(:) = SUM(D,DIM=1)        ! Sum down a column

Assuming the `owner-computes' rule, the following distributions would be examples of good HPF programming,

 !HPF$ DISTRIBUTE (BLOCK) ONTO P   :: A
 !HPF$ DISTRIBUTE (CYCLIC) ONTO P  :: B
 !HPF$ DISTRIBUTE (BLOCK) ONTO P   :: C  ! or (CYCLIC)
 !HPF$ DISTRIBUTE (*,BLOCK) ONTO P :: D ! or (*,CYCLIC)

The following facts were used in deciding which distribution methods were to be used:

• A is involved in neighbourhood calculations. A(3) is combined with A(1) and assigned to A(2)
• B an `odd shaped' inner section of B is used - in order to balance the load a CYCLIC distribution should be used.
• the calculation of an element of C involves a whole column of D. This means that every element of C should be aligned with the corresponding whole column of D.

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