Thanks; I saw you mention the paper before, but now I finally started reading it :) By the way, the paper *does* arrange an extra infrastructure for mappending only adjacent results. Looks like with a commutative monoid, a fold could be done in a fully distributed fashion, however it would no more be a scan.
2009/1/22 Dan Piponi <dpip...@gmail.com>: > On Wed, Jan 21, 2009 at 11:12 PM, Eugene Kirpichov <ekirpic...@gmail.com> > wrote: >> To my mind, in the map-reduce case you generally need a commutative >> monoid. Or, you need an extra infrastructure that mappend's only >> results from adjacent machines, or something like that. > > This is a good paper on the stuff I'm talking about: > http://citeseer.ist.psu.edu/blelloch90prefix.html It doesn't > explicitly mention monoids but it's all about associative operations > with identity. > -- > Dan > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
