Thanks for your answers. As said I'm using Neo4J 2.2.5 together with Spring-data. Could you please provide me an example of this Dijkstra approach. If needed I can upgrade the Neo4J library. I do want however to be able to use the spring data and Cypher approach.
Thanks in advance. Johan, Op dinsdag 17 mei 2016 22:57:31 UTC+2 schreef Craig Taverner: > > If you want the shortest path to interpret the length of the path based on > a cost function (for example shortest route on the map where the length of > the roads is the cost), then the 'shortestPath()' function is not the right > one. It can only consider all relationships as having the same weight and > that is the nature of the optimization of that algorithm. You need a > different algorithm like dijkstra or A-star. Cypher does not have > integration to the graph-algo component that provides those algorithms, so > you have three choices: > > * Write an exhaustive cypher query that finds all paths, sums the cost and > sorts and orders. This is fine on small graphs, but will be extremely slow > on even medium sides graphs. > * Use the graph-algo module through the Java API (unmanaged extensions in > neo4j 2.3 and earlier) > * Use the new procedures from Cypher in Neo4j 3.0 and later (these are > already wrapped for you at > https://github.com/neo4j-contrib/neo4j-apoc-procedures#graph-algorithms-work-in-progress > ) > > This last option is probably the easiest option, but I've not tried them > myself. Michael might know better how well they work. > > > On Tue, May 17, 2016 at 10:30 PM, Johan Kumps <johan...@gmail.com > <javascript:>> wrote: > >> What if I would like to get all shortest paths with the lowest cost >> without knowing how much this could be. I think by adding the query >> rel.cost < x will not work in this case? >> >> Op dinsdag 17 mei 2016 22:23:37 UTC+2 schreef Michael Hunger: >>> >>> Just add a WHERE clause (at least in Neo4j 3.x) >>> >>> WHERE ALL( rel in rels(path) WHERE rel.cost > 10) >>> >>> > Am 17.05.2016 um 15:19 schrieb Johan Kumps <johan...@gmail.com>: >>> > >>> > Hi, >>> > >>> > I'm currently calculating the shortest paths between 2 nodes via the >>> SEM_SIM relationship using the following query: >>> > >>> > @Query("MATCH (s:StartVertex {uuid:{0}}) , " >>> > + "(g:GoalVertex {uuid:{1}}) , " >>> > + "path = >>> shortestpath((s)-[:SEM_SIM*]-(g)) " >>> > + "RETURN path ORDER BY LENGTH(path) >>> DESC LIMIT 1") >>> > >>> > All this is working fine but I would like to be able to take a >>> relationship attribute like cost into account. How can I use this attribute >>> in the above query? >>> > >>> > Thanks in advance for the information >>> > >>> > Kind regards, >>> > Johan, >>> > >>> > >>> > >>> > >>> > -- >>> > You received this message because you are subscribed to the Google >>> Groups "Neo4j" group. >>> > To unsubscribe from this group and stop receiving emails from it, send >>> an email to neo4j+un...@googlegroups.com. >>> > For more options, visit https://groups.google.com/d/optout. >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "Neo4j" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to neo4j+un...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to neo4j+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
