Re: [Neo4j] Re: dijkstra bidirectional

[Axel Morgner]

Hi Antonio,

what you ask for is not something trivial one can quickly do over the 
weekend. So if you really need it, you sould perhaps ask for paid 
consolting, or offer a remuneration for this. I'm sure there are some 
top-notch people on this list being able to implement it.


Best,
Axel

Am 23.06.2014 10:28, schrieb Antonio Grimaldi:

I hope someone has developed Bidirectiona Dijkstra..
I need it.

Antonio

Il giorno giovedì 8 maggio 2014 17:04:32 UTC+2, Antonio Grimaldi ha 
scritto:


Hi,
Is there an implementation of Bidirectional Dijkstra?

Thanks
Antonio

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Re: [Neo4j] Re: dijkstra bidirectional

[Mattias Persson]

Sorry for not replying but time is a scarse resource :( I don't expect my
getting time for this the closest months. Perhaps there are others willing
to help out!

Take care
Best,
Mattias
Den 10 jun 2014 12:06 skrev "Antonio Grimaldi" <
antonio.grimaldim...@gmail.com>:

> Is* org.neo4j.graphalgo.impl.shortestpath.Dijkstra a *Bidirectional
> Dijkstra's implementation???
>
> Il giorno giovedì 8 maggio 2014 17:04:32 UTC+2, Antonio Grimaldi ha
> scritto:
>>
>> Hi,
>> Is there an implementation of Bidirectional Dijkstra?
>>
>> Thanks
>> Antonio
>>
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Re: [Neo4j] Re: dijkstra bidirectional

[Mattias Persson]

That is a good start, but I don't think that's enough as some more
coordination between the two sides will have to occur, otherwise the
traverser may stop before finding the best path out there. We'll just have
to read up on bidirectional Dijkstra algorithm and translate that into code.

My guess would be that there would have to be some custom code in
BestFirstSelector or a sub class thereof. And as I'm working on a bit of
other things, I don't have the time just yet to help you. But I'll see if I
can find time to at least read up on the algo a bit.


On Fri, May 9, 2014 at 11:00 AM, Antonio Grimaldi <
antonio.grimaldim...@gmail.com> wrote:

> Hi Mattias,
> thanks for your answer...
> As I'm a newbie, there would be some examples to follow?
>
> I only tried this modification in org.neo4j.graphalgo.impl.path.Dijkstra
> class, but i'm not sure that is enough..
> Can you help me?
>
> Thanks
>   private Traverser traverser( Node start, final Node end, boolean
> forMultiplePaths )
> {
>// return (lastTraverser = TRAVERSAL.expand( expander, stateFactory
> )
>  //   .order( new SelectorFactory( forMultiplePaths,
> costEvaluator ) )
>// .evaluator( Evaluators.includeWhereEndNodeIs( end )
> ).traverse( start ) );
>
> return   (lastTraverser = Traversal.bidirectionalTraversal()
>   .mirroredSides( TRAVERSAL.expand( expander )
>   .order( new SelectorFactory( forMultiplePaths,
> costEvaluator) ) )
>   .traverse( start, end ) );
>
> }
>
>
>
> Il giorno giovedì 8 maggio 2014 17:04:32 UTC+2, Antonio Grimaldi ha
> scritto:
>
>> Hi,
>> Is there an implementation of Bidirectional Dijkstra?
>>
>> Thanks
>> Antonio
>>
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