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Martin Junghanns commented on FLINK-2905: ----------------------------------------- Hi [~vkalavri]! Short question: As we do not have unique identifiers on edges, I was wondering what the expected output according to the edges would be. Please consider the simple example: V(G1): {code} 1,1 2,2 3,3 4,4 5,5 {code} V(G2) {code} 1,1 3,3 6,6 {code} E(G1) {code} 1,2,12 1,3,13 1,3,14 {code} E(G2) {code} 1,3,13 1,6,26 6,3,63 {code} Call {code:java} G' = G1.intersect(G2) {code} Expected output V(G') {code} 1,1 3,3 {code} Option 1: Considering (source, target) E(G') {code} 1,3,13 // from G2 1,3,13 // from G1 1,3,14 // from G1 {code} Option 2: Considering (source, target, value), no distinct E(G') {code} 1,3,13 // G1 1,3,13 // G2 {code} Option 3: Considering (source, target, value), distinct {code} 1,3,13 // G1 and G2 {code} The underlying question is: What makes edges unique? > Add intersect method to Graph class > ----------------------------------- > > Key: FLINK-2905 > URL: https://issues.apache.org/jira/browse/FLINK-2905 > Project: Flink > Issue Type: New Feature > Components: Gelly > Affects Versions: 0.10 > Reporter: Martin Junghanns > Assignee: Martin Junghanns > Priority: Minor > > Currently, the Gelly Graph supports the set operations > {{Graph.union(otherGraph)}} and {{Graph.difference(otherGraph)}}. It would be > nice to have a {{Graph.intersect(otherGraph)}} method, where the resulting > graph contains all vertices and edges contained in both input graphs. -- This message was sent by Atlassian JIRA (v6.3.4#6332)