It is a very frequent event in data parallel programming to group a number of processors to perform definite tasks. To reach this goal, HPF gives a directive called PROCESSORS directive. This directive declares a conceptual processor grid. In other words, the PROCESSORS directive is used to show the shape and size of an array of abstract processors. These do not have to be of the similar shape as the underlying hardware. The syntax of a PROCESSORS directive is:
!HPF$ PROCESSORS array_name (dim1, dim 2, ....dim n)
Where array_name is collective name of abstract processors. dim i specifies the size of ith
dimension of array_name.
!HPF$ PROCESSORS P (10)
This introduce a set of 10 abstract processors, assigning them the collective name P.
!HPF$ PROCESSORS Q (4, 4)
It introduces 16 abstract processors in a 4 by 4 array.