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author | kj-ki <kikushima.kenji@lab.ntt.co.jp> | 2015-01-06 09:49:37 -0800 |
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committer | Ankur Dave <ankurdave@gmail.com> | 2015-01-06 09:49:37 -0800 |
commit | 5e3ec1110495899a298313c4aa9c6c151c1f54da (patch) | |
tree | b7594e143573bc7facb4af3022fc461c71e81558 /graphx/src/main | |
parent | a6394bc2c094c6c662237236c2effa2dabe67910 (diff) | |
download | spark-5e3ec1110495899a298313c4aa9c6c151c1f54da.tar.gz spark-5e3ec1110495899a298313c4aa9c6c151c1f54da.tar.bz2 spark-5e3ec1110495899a298313c4aa9c6c151c1f54da.zip |
[Minor] Fix comments for GraphX 2D partitioning strategy
The sum of vertices on matrix (v0 to v11) is 12. And, I think one same block overlaps in this strategy.
This is minor PR, so I didn't file in JIRA.
Author: kj-ki <kikushima.kenji@lab.ntt.co.jp>
Closes #3904 from kj-ki/fix-partitionstrategy-comments and squashes the following commits:
79829d9 [kj-ki] Fix comments for 2D partitioning.
Diffstat (limited to 'graphx/src/main')
-rw-r--r-- | graphx/src/main/scala/org/apache/spark/graphx/PartitionStrategy.scala | 6 |
1 files changed, 3 insertions, 3 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 13033fee0e..7372dfbd9f 100644 --- a/graphx/src/main/scala/org/apache/spark/graphx/PartitionStrategy.scala +++ b/graphx/src/main/scala/org/apache/spark/graphx/PartitionStrategy.scala @@ -32,9 +32,9 @@ trait PartitionStrategy extends Serializable { object PartitionStrategy { /** * Assigns edges to partitions using a 2D partitioning of the sparse edge adjacency matrix, - * guaranteeing a `2 * sqrt(numParts)` bound on vertex replication. + * guaranteeing a `2 * sqrt(numParts) - 1` bound on vertex replication. * - * Suppose we have a graph with 11 vertices that we want to partition + * Suppose we have a graph with 12 vertices that we want to partition * over 9 machines. We can use the following sparse matrix representation: * * <pre> @@ -61,7 +61,7 @@ object PartitionStrategy { * that edges adjacent to `v11` can only be in the first column of blocks `(P0, P3, * P6)` or the last * row of blocks `(P6, P7, P8)`. As a consequence we can guarantee that `v11` will need to be - * replicated to at most `2 * sqrt(numParts)` machines. + * replicated to at most `2 * sqrt(numParts) - 1` machines. * * Notice that `P0` has many edges and as a consequence this partitioning would lead to poor work * balance. To improve balance we first multiply each vertex id by a large prime to shuffle the |