[jira] [Created] (SPARK-3650) Triangle Count handles reverse edges incorrectly

["Joseph E. Gonzalez (JIRA)" <ji...@apache.org>]

Joseph E. Gonzalez created SPARK-3650:
-----------------------------------------

             Summary: Triangle Count handles reverse edges incorrectly
                 Key: SPARK-3650
                 URL: https://issues.apache.org/jira/browse/SPARK-3650
             Project: Spark
          Issue Type: Bug
          Components: GraphX
    Affects Versions: 1.1.0
            Reporter: Joseph E. Gonzalez


The triangle count implementation assumes that edges are aligned in a canonical direction.  As stated in the documentation:

```
Note that the input graph should have its edges in canonical direction
 * (i.e. the `sourceId` less than `destId`)
```

However the TriangleCount algorithm does not verify that this condition holds and indeed even the unit tests exploits this functionality:

~~~
val triangles = Array(0L -> 1L, 1L -> 2L, 2L -> 0L) ++
        Array(0L -> -1L, -1L -> -2L, -2L -> 0L)
      val rawEdges = sc.parallelize(triangles, 2)
      val graph = Graph.fromEdgeTuples(rawEdges, true).cache()
      val triangleCount = graph.triangleCount()
      val verts = triangleCount.vertices
      verts.collect().foreach { case (vid, count) =>
        if (vid == 0) {
          assert(count === 4)  // <-- Should be 2
        } else {
          assert(count === 2) // <-- Should be 1
        }
      }
~~~






--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org