From 5820961289eb98e45eb467efa316c7592b8d619c Mon Sep 17 00:00:00 2001
From: Brennon York <brennon.york@capitalone.com>
Date: Tue, 10 Feb 2015 14:57:00 -0800
Subject: [PATCH] [SPARK-5343][GraphX]: ShortestPaths traverses backwards
Corrected the logic with ShortestPaths so that the calculation will run forward rather than backwards. Output before looked like:
```scala
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:
```scala
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()))
```
Author: Brennon York <brennon.york@capitalone.com>
Closes #4478 from brennonyork/SPARK-5343 and squashes the following commits:
aa57f83 [Brennon York] updated to set ShortestPaths to run 'forward' rather than 'backward'
---
.../scala/org/apache/spark/graphx/lib/ShortestPaths.scala | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/graphx/src/main/scala/org/apache/spark/graphx/lib/ShortestPaths.scala b/graphx/src/main/scala/org/apache/spark/graphx/lib/ShortestPaths.scala
index 590f047495..179f284381 100644
--- a/graphx/src/main/scala/org/apache/spark/graphx/lib/ShortestPaths.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/lib/ShortestPaths.scala
@@ -61,8 +61,8 @@ object ShortestPaths {
}
def sendMessage(edge: EdgeTriplet[SPMap, _]): Iterator[(VertexId, SPMap)] = {
- val newAttr = incrementMap(edge.srcAttr)
- if (edge.dstAttr != addMaps(newAttr, edge.dstAttr)) Iterator((edge.dstId, newAttr))
+ val newAttr = incrementMap(edge.dstAttr)
+ if (edge.srcAttr != addMaps(newAttr, edge.srcAttr)) Iterator((edge.srcId, newAttr))
else Iterator.empty
}
--
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