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ASF GitHub Bot commented on FLINK-3780: --------------------------------------- Github user greghogan commented on a diff in the pull request: https://github.com/apache/flink/pull/1980#discussion_r63892035 --- Diff: docs/apis/batch/libs/gelly.md --- @@ -2051,6 +2052,26 @@ The algorithm takes a directed, vertex (and possibly edge) attributed graph as i vertex represents a group of vertices and each edge represents a group of edges from the input graph. Furthermore, each vertex and edge in the output graph stores the common group value and the number of represented elements. +### Jaccard Index + +#### Overview +The Jaccard Index measures the similarity between vertex neighborhoods. Scores range from 0.0 (no common neighbors) to +1.0 (all neighbors are common). + +#### Details +Counting common neighbors for pairs of vertices is equivalent to counting the two-paths consisting of two edges --- End diff -- I've also seen triad to mean any three vertices and triplet to mean any three connected vertices. I'll rework this section. > Jaccard Similarity > ------------------ > > Key: FLINK-3780 > URL: https://issues.apache.org/jira/browse/FLINK-3780 > Project: Flink > Issue Type: New Feature > Components: Gelly > Affects Versions: 1.1.0 > Reporter: Greg Hogan > Assignee: Greg Hogan > Fix For: 1.1.0 > > > Implement a Jaccard Similarity algorithm computing all non-zero similarity > scores. This algorithm is similar to {{TriangleListing}} but instead of > joining two-paths against an edge list we count two-paths. > {{flink-gelly-examples}} currently has {{JaccardSimilarityMeasure}} which > relies on {{Graph.getTriplets()}} so only computes similarity scores for > neighbors but not neighbors-of-neighbors. > This algorithm is easily modified for other similarity scores such as > Adamic-Adar similarity where the sum of endpoint degrees is replaced by the > degree of the middle vertex. -- This message was sent by Atlassian JIRA (v6.3.4#6332)