CODEWITHSUNDEEP
graphneo4jcypher
Vineel
Vineel

Reputation: 1788

How to write this in Cypher

I have around 644 nodes in my graph database(Neo4j) . I need to compute distances between all these 644 nodes and display it visually in the GUI. I want to pre-compute and store the distances between every two pairs of nodes in the database itself rather than retrieving the nodes on to the server and then finding the distances between them on the fly and then showing on the GUI.

I want to understand how to write such a query in CYPHER. Please let me know.

Upvotes: 0

Views: 59

Answers (1)

Michael Hunger
Michael Hunger

Reputation: 41706

I think this can work:

// half cross product
match (a),(b)
where id(a) < id(b)
match p=shortestPath((a)-[*]-(b))
with a,b,length(p) as l
create (a)-[:DISTANCE {distance:l}]->(b)

Set 4950 properties, created 4950 relationships, returned 0 rows in 4328 ms

But the browser viz will blow up with this, just that you know.

Regarding your distance measure (it won't be that fast but should work):

MATCH (a:User)-[:READ]->(book)<-[:READ]-(b:User)
WITH a,b,count(*) as common,
     length(a-[:READ]->()) as a_read,
     length(b-[:READ]->()) as b_read
CREATE UNIQUE (a)-[:DISTANCE {distance:common/(a_read+b_read-common)}]-(b)

Upvotes: 1

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