Hi all,
I'm following Noe4j's online document at https://neo4j.com/docs/graph-data-science/current/alpha-algorithms/minimum-weight-spanning-tree/ , it seems that the Cypher to query K-Spanning tree doesn't work:
MATCH (n:Place)
WITH n.id AS Place, n.kminst AS Partition, count(*) AS count
WHERE count = 3
RETURN Place, Partition
Should it be modifyed to the following?
MATCH (n:Place)
WITH n.kminst AS Partition, count(*) AS count
WHERE count = 3
MATCH (n:Place)
WHERE n.kminst=Partition
RETURN n
I'v downloaded the example transport data of the book <Graph Algorithms> from data · master · examples / Graph Algorithms · GitLab, and loaded it into a graph database, all path algorithms of the package is O.K. , except the K-Spanning tree, can't figure out how to make it work.
MATCH (source:Place {id: "Amsterdam"})
CALL gds.alpha.spanningTree.kmin.write({
nodeProjection:'Place',
relationshipProjection:{
EROAD:{
type:'EROAD',
properties:'distance',
orientation:'NATURAL'
}},
startNodeId:id(source),
relationshipWeightProperty:'distance',
writeProperty: 'kminst',
k: 3
})
YIELD createMillis, computeMillis, writeMillis, effectiveNodeCount
RETURN createMillis, computeMillis, writeMillis, effectiveNodeCount
MATCH (n:Place)
WITH n.kminst AS partition, count(*) AS count
RETURN partition, count
There's no partition gets the count value 3 (which is the value of parameter k), so don't know how to extract the result with a Cypher like this:
MATCH (n:Place)
WITH n.kminst AS Partition, count(*) AS count
WHERE count = 3
MATCH (n:Place)
WHERE n.kminst=Partition
RETURN n
Any idea is appreciated.