Parallelization of algorithms by explicit partitioning

In order to utilize parallel computers, four approaches, broadly speaking, to the provision of parallel software have been followed: (1) automatic production of parallel code by parallelizing—compilers which act on sequential programs written in existing languages; (2) "add on" features to existing languages that enable the programmer to make use of the parallel computer—these are specific to each machine; (3) full-blown parallel languages—these could be completely new languages, but usually they are derived from existing languages; (4) the provision of tools to aid the programmer in the detection of inherent parallelism in a given algorithm and in the design and implementation of parallel programs. [Continues.]