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Theoretical Background

  The space-time mapping methods we study are based on the polytope model of nested loops, and on some extensions of it.

The polytope model is a useful model of computation for the static parallelization of nested [Len93]. The model represents the atomic iteration steps of d perfectly nested as the points of a polytope in tex2html_wrap_inline1252 ; each loop defines the extent of the polytope in one dimension. The faces of the polytope correspond to the bounds of the loops; they are all known at compile time. This enables the compile-time discovery of maximal parallelism--relative to the choices available within the method, which are limited by the data dependences of the source program and by the requirement that the space-time mapping defining the parallelism be affine.





Martin Griebl
Wed Apr 24 11:24:00 MET DST 1996