this is perhaps worth watching:

http://www.youtube.com/watch?v=BT-piFBP4fE&feature=channel

it deals with finding the shortest path in a graph using MR.  here at
work i don't have audio working so i'm not 100% sure that this is the
best way to do it, but it is a start.

Miles

2009/1/29 Mark Kerzner <[email protected]>:
> Oh, hail to the creator of Luke!Mark
>
> On Thu, Jan 29, 2009 at 11:20 AM, Andrzej Bialecki <[email protected]> wrote:
>
>> Hi,
>>
>> I'm looking for an advice. I need to process a directed graph encoded as a
>> list of <from, to> pairs. The goal is to compute a list of longest paths in
>> the graph. There is no guarantee that the graph is acyclic, so there should
>> be some mechanism to detect cycles.
>>
>> Currently I'm using a simple approach consisting of the following: I encode
>> the graph as <vertex, <neighbor, direction, distance>>, and extending the
>> paths by one degree at a time. This means that in order to find the longest
>> path of degree N it takes N + 1 map-reduce jobs.
>>
>> Are you perhaps aware of a smarter way to do it? I would appreciate any
>> pointers.
>>
>> --
>> Best regards,
>> Andrzej Bialecki     <><
>>  ___. ___ ___ ___ _ _   __________________________________
>> [__ || __|__/|__||\/|  Information Retrieval, Semantic Web
>> ___|||__||  \|  ||  |  Embedded Unix, System Integration
>> http://www.sigram.com  Contact: info at sigram dot com
>>
>>
>



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