From 2b36344f588d4e7357ce9921dc656e2389ba1dea Mon Sep 17 00:00:00 2001
From: Sean Owen <sowen@cloudera.com>
Date: Thu, 3 Jul 2014 11:54:51 -0700
Subject: [PATCH] SPARK-1675. Make clear whether computePrincipalComponents
requires centered data
Just closing out this small JIRA, resolving with a comment change.
Author: Sean Owen <sowen@cloudera.com>
Closes #1171 from srowen/SPARK-1675 and squashes the following commits:
45ee9b7 [Sean Owen] Add simple note that data need not be centered for computePrincipalComponents
---
.../org/apache/spark/mllib/linalg/distributed/RowMatrix.scala | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mllib/src/main/scala/org/apache/spark/mllib/linalg/distributed/RowMatrix.scala b/mllib/src/main/scala/org/apache/spark/mllib/linalg/distributed/RowMatrix.scala
index 1a0073c9d4..695e03b736 100644
--- a/mllib/src/main/scala/org/apache/spark/mllib/linalg/distributed/RowMatrix.scala
+++ b/mllib/src/main/scala/org/apache/spark/mllib/linalg/distributed/RowMatrix.scala
@@ -347,6 +347,8 @@ class RowMatrix(
* The principal components are stored a local matrix of size n-by-k.
* Each column corresponds for one principal component,
* and the columns are in descending order of component variance.
+ * The row data do not need to be "centered" first; it is not necessary for
+ * the mean of each column to be 0.
*
* @param k number of top principal components.
* @return a matrix of size n-by-k, whose columns are principal components
--
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