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From Jake Mannix <jake.man...@gmail.com>
Subject Re: Primitives vs Objects (the Movie!)
Date Wed, 07 Sep 2011 22:49:16 GMT
On Wed, Sep 7, 2011 at 10:43 PM, Dmitriy Ryaboy <dmitriy@twitter.com> wrote:

> Something else to think about -- in some cases you may want to
> implement extreme compression of the edge list. For example, we might
> want to calculate n-th degree reach for all nodes in a graph. Given a
> graph with a few nodes with lots of incoming edges ("biebernodes", we
> call them), anything that jumps across them winds up essentially
> replicating large chunks of the graph to each node. Things like RLE
> might make sense when you are doing that sort of thing in memory and
> only have so many terabytes of that lying around.
>

Right, in some cases, we may want to not have edge values at all.  Just
existence in the vertex's target list of a target vertex id denotes
"connection",
and so "SortedMap<I, Edge<E,I>>" gets replaced with "long[]".

  -jake

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