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From Claudio Martella <claudio.marte...@gmail.com>
Subject Re: Information
Date Wed, 26 Mar 2014 12:27:34 GMT
It looks like you're expecting to use Giraph in an online fashion, such as
you would use a database to answer queries within milliseconds or seconds.
Giraph is an offline batch processing system.


On Wed, Mar 26, 2014 at 11:11 AM, Angelo Immediata <angeloimm@gmail.com>wrote:

> Hi there
>
> In my project I have to implement a routing system with good performance;
> at the beginning this system should be able in giving routes information
> only for one italian region (Lombardia) but it could be used for the whole
> Italy (or world....)
> Let's stop to the Lombardia for now. By reading OSM files I can create my
> own graph in the best format i can use it; then I need to use Dijkstra (or
> any other algorithm) in order to propose to the user K possible paths from
> point A to point B (K becouse i need to show to the customer also the
> alternatives). I can't use Contraction Herarchy algorithm becouse I need to
> take care of external events that can modify the weights on my built graph
> and this implies that I should create the "contracted" graph once again and
> this can be a very onerous operation
>
> By my experimentations, I saw that by reading the Lombardia OSM file I
> should create a graph with around 1 million of vertexes and 6 million of
> edges and I was thinking to use Giraph to solve my issue (I saw this link
> http://giraph.apache.org/intro.html where you talked about shortestpaths
> problem
> I have a couple of question for you giraph/hadoop gurus
>
>    - does it make sense to use giraph for my scenario?
>    - must i respect some graph format to pass to the giraph algorithm in
>    order to have K shortest paths from point A to point B? If so....which
>    format should I respect?
>    - what would be perfomance by using giraph? I know that Dijstra
>    algorithm problem is that it is slow.....by using giraph will I be able in
>    improving its performances on very large graph?
>
> I know these can seem very basic questions, but I'm pretty new to giraph
> and I'm trying to understand it
>
> Thank you
> Angelo
>



-- 
   Claudio Martella

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