%T Mapping a process network onto a processor network
%A  Francis C. M. Lau,  K. M. Shea
%E  Charlie Askew
%B OUG\-9: Occam and the Transputer \-\- Research and Applications
%X This paper addresses the problem of mapping an Occam program
   onto a transputer network. This mapping is essentially a
   graph embedding (or related) problem: i.e., find a function
   f: N \-> { 1, 2.....| M |} such that certain performance
   criteria would be satisfied, where N is the set of processes
   in the Occam program (the graph) and M is the set of
   processors in the transputer network. Depending on the
   complexity of the graph as well as the target transputer
   network, many of these problems are NP\-complete [1,2]. This
   paper addresses not the mapping algorithm and how it may
   achieve optimality, which is a policy matter, but the
   mechanism of mapping \- that is, given a mapping algorithm,
   what exactly do we do to transform the program into an
   equivalent program that is ready to be downloaded onto the
   transputer network. Our answer is a precompiler which we
   have successfully implemented. We discuss several important
   problems that occurred in our construction of the mapping
   procedure, and briefly describe the actual implementation of
   the precompiler.