Pregel in 3.2, how to treat undirected edges

[Mike Atambo]

With newer versions of arangodb, its now only possible to create directed edges,  but in the pregel docs:

 https://docs.arangodb.com/devel/Manual/Graphs/Pregel/    there is this little snippet "Should work best on undirected graphs, results on directed graphs might vary "

in the topic on  'Community Detection: Label Propagation'   does this mean we need to make reciprocal edges (two edges one pointing opposite) for all neighbours?

Mike.

[Simon G]

Yes you will have to specify reciprocal edges in the community edition. In an ArangoDB cluster the community edition does only store an edge document on one DBServer, but for an undirected graph you need the edge on both DBServers.

You will have to insert two edge documents with matching '_from' and '_to' attributes. For pregel you also need to ensure that both documents are sharded correctly after the '_from' attribute:
https://docs.arangodb.com/devel/Manual/Graphs/Pregel/#requirements-for-collections-in-a-cluster-non-smart-graph