revert to have lazy in shift array.

DB Tsai · DB Tsai · commit 85885a98125e · 2014-11-24T23:57:14.000-08:00
diff --git a/mllib/src/main/scala/org/apache/spark/mllib/feature/StandardScaler.scala b/mllib/src/main/scala/org/apache/spark/mllib/feature/StandardScaler.scala
@@ -85,7 +85,10 @@ class StandardScalerModel private[mllib] (
     f
   }
 
-  private val shift: Array[Double] = mean.toArray
+  // Since `shift` will be only used in `withMean` branch, we have it as
+  // `lazy val` so it will be evaluated in that branch. Note that we don't
+  // want to create this array multiple times in `transform` function.
+  private lazy val shift: Array[Double] = mean.toArray
 
   /**
    * Applies standardization transformation on a vector.

Original file line number	Diff line number	Diff line change
`@@ -85,7 +85,10 @@ class StandardScalerModel private[mllib] (`
`85`	`85`	`f`
`86`	`86`	`}`
`87`	`87`
`88`		`- private val shift: Array[Double] = mean.toArray`
	`88`	+ // Since `shift` will be only used in `withMean` branch, we have it as
	`89`	+ // `lazy val` so it will be evaluated in that branch. Note that we don't
	`90`	+ // want to create this array multiple times in `transform` function.
	`91`	`+ private lazy val shift: Array[Double] = mean.toArray`
`89`	`92`
`90`	`93`	`/**`
`91`	`94`	`* Applies standardization transformation on a vector.`