SPARK-1675. Make clear whether computePrincipalComponents requires centered data

srowen · mengxr · commit 2b36344f588d · 2014-07-03T11:54:51.000-07:00
Just closing out this small JIRA, resolving with a comment change. Author: Sean Owen <sowen@cloudera.com> Closes apache#1171 from srowen/SPARK-1675 and squashes the following commits: 45ee9b7 [Sean Owen] Add simple note that data need not be centered for computePrincipalComponents
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
@@ -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

Original file line number	Diff line number	Diff line change
`@@ -347,6 +347,8 @@ class RowMatrix(`
`347`	`347`	`* The principal components are stored a local matrix of size n-by-k.`
`348`	`348`	`* Each column corresponds for one principal component,`
`349`	`349`	`* and the columns are in descending order of component variance.`
	`350`	`+ * The row data do not need to be "centered" first; it is not necessary for`
	`351`	`+ * the mean of each column to be 0.`
`350`	`352`	`*`
`351`	`353`	`* @param k number of top principal components.`
`352`	`354`	`* @return a matrix of size n-by-k, whose columns are principal components`