[SPARK-6893][ML] default pipeline parameter handling in python

Same as #5431 but for Python. jkbradley

Author: Xiangrui Meng <meng@databricks.com>

Closes #5534 from mengxr/SPARK-6893 and squashes the following commits:

d3b519b [Xiangrui Meng] address comments
ebaccc6 [Xiangrui Meng] style update
fce244e [Xiangrui Meng] update explainParams with test
4d6b07a [Xiangrui Meng] add tests
5294500 [Xiangrui Meng] update default param handling in python

1 files changed, 2 insertions, 1 deletions

diff --git a/python/pyspark/ml/classification.py b/python/pyspark/ml/classification.py
index 7f42de531f..d7bc09fd77 100644
--- a/python/pyspark/ml/classification.py
+++ b/python/pyspark/ml/classification.py
@@ -59,6 +59,7 @@ class LogisticRegression(JavaEstimator, HasFeaturesCol, HasLabelCol, HasPredicti
                  maxIter=100, regParam=0.1)
         """
         super(LogisticRegression, self).__init__()
+        self._setDefault(maxIter=100, regParam=0.1)
         kwargs = self.__init__._input_kwargs
         self.setParams(**kwargs)
 
@@ -71,7 +72,7 @@ class LogisticRegression(JavaEstimator, HasFeaturesCol, HasLabelCol, HasPredicti
         Sets params for logistic regression.
         """
         kwargs = self.setParams._input_kwargs
-        return self._set_params(**kwargs)
+        return self._set(**kwargs)
 
     def _create_model(self, java_model):
         return LogisticRegressionModel(java_model)