[SPARK-5343][GraphX]: ShortestPaths traverses backwards

[brennonyork]

Corrected the logic with ShortestPaths so that the calculation will run forward rather than backwards. Output before looked like:

import org.apache.spark.graphx._
val g = Graph(sc.makeRDD(Array((1L,""), (2L,""), (3L,""))), sc.makeRDD(Array(Edge(1L,2L,""), Edge(2L,3L,""))))
lib.ShortestPaths.run(g,Array(3)).vertices.collect
// res0: Array[(org.apache.spark.graphx.VertexId, org.apache.spark.graphx.lib.ShortestPaths.SPMap)] = Array((1,Map()), (3,Map(3 -> 0)), (2,Map()))
lib.ShortestPaths.run(g,Array(1)).vertices.collect
// res1: Array[(org.apache.spark.graphx.VertexId, org.apache.spark.graphx.lib.ShortestPaths.SPMap)] = Array((1,Map(1 -> 0)), (3,Map(1 -> 2)), (2,Map(1 -> 1)))

And new output after the changes looks like:

import org.apache.spark.graphx._
val g = Graph(sc.makeRDD(Array((1L,""), (2L,""), (3L,""))), sc.makeRDD(Array(Edge(1L,2L,""), Edge(2L,3L,""))))
lib.ShortestPaths.run(g,Array(3)).vertices.collect
// res0: Array[(org.apache.spark.graphx.VertexId, org.apache.spark.graphx.lib.ShortestPaths.SPMap)] = Array((1,Map(3 -> 2)), (2,Map(3 -> 1)), (3,Map(3 -> 0)))
lib.ShortestPaths.run(g,Array(1)).vertices.collect
// res1: Array[(org.apache.spark.graphx.VertexId, org.apache.spark.graphx.lib.ShortestPaths.SPMap)] = Array((1,Map(1 -> 0)), (2,Map()), (3,Map()))

[AmplabJenkins]

Can one of the admins verify this patch?

[ankurdave]

ok to test

[SparkQA]

Test build #27119 has started for PR 4478 at commit aa57f83.

• This patch merges cleanly.

[SparkQA]

Test build #27119 has finished for PR 4478 at commit aa57f83.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test FAILed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/27119/
Test FAILed.

[brennonyork]

Can we get this retested? Looks like it failed on a timing test unrelated to the GraphX portion of things.

[ankurdave]

Jenkins, retest this please.

[SparkQA]

Test build #27187 has started for PR 4478 at commit aa57f83.

• This patch merges cleanly.

[SparkQA]

Test build #27187 has finished for PR 4478 at commit aa57f83.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test PASSed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/27187/
Test PASSed.

[ankurdave]

Thanks! Merged into master & branch-1.3.