JuliaLang/julia — pull request #475 by ajdecon (2012-02-27 18:09:57+00:00)
Title: Added parallel wordcount example.

Now that the map-reduce wordcount is working, I thought it might make a good example to include as a simple illustration of spawn-fetch parallelization. I've tried to add enough comments to make it a good educational tool, explaining what each part does.

Currently the major limitation of this implementation is that the "reduce" is single-threaded. I haven't been able to find a way to perform a key-sort-and-separate step on the HashTables returned by the map step, to allow parallelizing reduce, that isn't just as slow as doing the reduce on a single node anyway.