Fix pagerank yelp query (#431)

Author: tomasonjo

doc/pagerank.adoc

@@ -115,7 +115,7 @@ For now there is no option to load the the relationship as undirected, but we ca
 Undirected graph can be represented as https://en.wikipedia.org/wiki/Bidirected_graph[Bidirected graph], that is a directed graph in which the reverse of every relationship is also a relationship. 
 
 We do not have to save this reversed relationship, we can project it using *cypher loading*.
-We load all relationships and then use `UNION` to also load all relationships with reversed directions.
+Note that relationship query does not specify direction of the relationship. 
 This is applicable to all other algorithms, that use *cypher loading*.
 
 .Running algorithm on Yelp social network

doc/scripts/pagerank.cypher

@@ -44,4 +44,16 @@ CALL algo.pageRank(
 'MATCH (p1:Page)-[:Link]->(p2:Page) RETURN id(p1) as source, id(p2) as target',
 {graph:'cypher', iterations:5, write: true});
 
-// end::cypher-loading[]
+// end::cypher-loading[]
+
+// tag::pagerank-stream-yelp-social[]
+
+call algo.pageRank.stream(
+'MATCH (u:User) WHERE exists( (u)-[:FRIENDS]-() ) RETURN id(u) as id',
+'MATCH (u1:User)-[:FRIENDS]-(u2:User) RETURN id(u1) as source, id(u2) as target',
+{graph:'cypher'}
+) yield node,score with node,score order by score desc limit 10 
+return node {.name, .review_count, .average_stars,.useful,.yelping_since,.funny},score;
+
+// end::pagerank-stream-yelp-social[]
+

doc/scripts/yelp-import.cypher

@@ -103,16 +103,3 @@ ON CREATE SET cr.weight = weight
 ',{batchSize: 1});
 
 // end::coocurence-graph[]
-
-// tag:pagerank-stream-yelp-social[]
-
-call algo.pageRank.stream(
-'MATCH (u:User) WHERE exists( (u)-[:FRIENDS]-() ) RETURN id(u) as id',
-'MATCH (u1:User)-[:FRIENDS]->(u2:User) RETURN id(u1) as source, id(u2) as target
- UNION
- MATCH (u1:User)-[:FRIENDS]->(u2:User) RETURN id(u2) as source, id(u1) as target',
-{graph:'cypher'}
-) yield node,score with node,score order by score desc limit 10 
-return node {.name, .review_count, .average_stars,.useful,.yelping_since,.funny},score;
-
-// end:pagerank-stream-yelp-social[]