[SPARK-10668] [ML] Use WeightedLeastSquares in LinearRegression with L…

…2 regularization if the number of features is small

Author: lewuathe <lewuathe@me.com>
Author: Lewuathe <sasaki@treasure-data.com>
Author: Kai Sasaki <sasaki@treasure-data.com>
Author: Lewuathe <lewuathe@me.com>

Closes #8884 from Lewuathe/SPARK-10668.

1 files changed, 2 insertions, 1 deletions

diff --git a/mllib/src/test/java/org/apache/spark/ml/regression/JavaLinearRegressionSuite.java b/mllib/src/test/java/org/apache/spark/ml/regression/JavaLinearRegressionSuite.java
index 91c589d00a..4fb0b0d109 100644
--- a/mllib/src/test/java/org/apache/spark/ml/regression/JavaLinearRegressionSuite.java
+++ b/mllib/src/test/java/org/apache/spark/ml/regression/JavaLinearRegressionSuite.java
@@ -61,6 +61,7 @@ public class JavaLinearRegressionSuite implements Serializable {
   public void linearRegressionDefaultParams() {
     LinearRegression lr = new LinearRegression();
     assertEquals("label", lr.getLabelCol());
+    assertEquals("auto", lr.getSolver());
     LinearRegressionModel model = lr.fit(dataset);
     model.transform(dataset).registerTempTable("prediction");
     DataFrame predictions = jsql.sql("SELECT label, prediction FROM prediction");
@@ -75,7 +76,7 @@ public class JavaLinearRegressionSuite implements Serializable {
     // Set params, train, and check as many params as we can.
     LinearRegression lr = new LinearRegression()
         .setMaxIter(10)
-        .setRegParam(1.0);
+        .setRegParam(1.0).setSolver("l-bfgs");
     LinearRegressionModel model = lr.fit(dataset);
     LinearRegression parent = (LinearRegression) model.parent();
     assertEquals(10, parent.getMaxIter());