From f938a155b2a9c126b292d5403aca31de83d5105a Mon Sep 17 00:00:00 2001
From: "Joseph E. Gonzalez" <joseph.e.gonzalez@gmail.com>
Date: Sun, 11 May 2014 18:33:46 -0700
Subject: [PATCH] Fix error in 2d Graph Partitioner
Their was a minor bug in which negative partition ids could be generated when constructing a 2D partitioning of a graph. This could lead to an inefficient 2D partition for large vertex id values.
Author: Joseph E. Gonzalez <joseph.e.gonzalez@gmail.com>
Closes #709 from jegonzal/fix_2d_partitioning and squashes the following commits:
937c562 [Joseph E. Gonzalez] fixing bug in 2d partitioning algorithm where negative partition ids could be generated.
---
.../scala/org/apache/spark/graphx/PartitionStrategy.scala | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/graphx/src/main/scala/org/apache/spark/graphx/PartitionStrategy.scala b/graphx/src/main/scala/org/apache/spark/graphx/PartitionStrategy.scala
index 0470d74cf9..1526ccef06 100644
--- a/graphx/src/main/scala/org/apache/spark/graphx/PartitionStrategy.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/PartitionStrategy.scala
@@ -78,8 +78,8 @@ object PartitionStrategy {
override def getPartition(src: VertexId, dst: VertexId, numParts: PartitionID): PartitionID = {
val ceilSqrtNumParts: PartitionID = math.ceil(math.sqrt(numParts)).toInt
val mixingPrime: VertexId = 1125899906842597L
- val col: PartitionID = ((math.abs(src) * mixingPrime) % ceilSqrtNumParts).toInt
- val row: PartitionID = ((math.abs(dst) * mixingPrime) % ceilSqrtNumParts).toInt
+ val col: PartitionID = (math.abs(src * mixingPrime) % ceilSqrtNumParts).toInt
+ val row: PartitionID = (math.abs(dst * mixingPrime) % ceilSqrtNumParts).toInt
(col * ceilSqrtNumParts + row) % numParts
}
}
--
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