[SPARK-14107][PYSPARK][ML] Add seed as named argument to GBTs in pyspark

## What changes were proposed in this pull request?

GBTs in pyspark previously had seed parameters, but they could not be passed as keyword arguments through the class constructor. This patch adds seed as a keyword argument and also sets default value.

## How was this patch tested?

Doc tests were updated to pass a random seed through the GBTClassifier and GBTRegressor constructors.

Author: sethah <[email protected]>

Closes apache#11944 from sethah/SPARK-14107.

Author: sethah

python/pyspark/ml/classification.py

@@ -520,7 +520,7 @@ class GBTClassifier(JavaEstimator, HasFeaturesCol, HasLabelCol, HasPredictionCol
     >>> stringIndexer = StringIndexer(inputCol="label", outputCol="indexed")
     >>> si_model = stringIndexer.fit(df)
     >>> td = si_model.transform(df)
-    >>> gbt = GBTClassifier(maxIter=5, maxDepth=2, labelCol="indexed")
+    >>> gbt = GBTClassifier(maxIter=5, maxDepth=2, labelCol="indexed", seed=42)
     >>> model = gbt.fit(td)
     >>> allclose(model.treeWeights, [1.0, 0.1, 0.1, 0.1, 0.1])
     True
@@ -543,19 +543,19 @@ class GBTClassifier(JavaEstimator, HasFeaturesCol, HasLabelCol, HasPredictionCol
     def __init__(self, featuresCol="features", labelCol="label", predictionCol="prediction",
                  maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0,
                  maxMemoryInMB=256, cacheNodeIds=False, checkpointInterval=10, lossType="logistic",
-                 maxIter=20, stepSize=0.1):
+                 maxIter=20, stepSize=0.1, seed=None):
         """
         __init__(self, featuresCol="features", labelCol="label", predictionCol="prediction", \
                  maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0, \
                  maxMemoryInMB=256, cacheNodeIds=False, checkpointInterval=10, \
-                 lossType="logistic", maxIter=20, stepSize=0.1)
+                 lossType="logistic", maxIter=20, stepSize=0.1, seed=None)
         """
         super(GBTClassifier, self).__init__()
         self._java_obj = self._new_java_obj(
             "org.apache.spark.ml.classification.GBTClassifier", self.uid)
         self._setDefault(maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0,
                          maxMemoryInMB=256, cacheNodeIds=False, checkpointInterval=10,
-                         lossType="logistic", maxIter=20, stepSize=0.1)
+                         lossType="logistic", maxIter=20, stepSize=0.1, seed=None)
         kwargs = self.__init__._input_kwargs
         self.setParams(**kwargs)
 
@@ -564,12 +564,12 @@ def __init__(self, featuresCol="features", labelCol="label", predictionCol="pred
     def setParams(self, featuresCol="features", labelCol="label", predictionCol="prediction",
                   maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0,
                   maxMemoryInMB=256, cacheNodeIds=False, checkpointInterval=10,
-                  lossType="logistic", maxIter=20, stepSize=0.1):
+                  lossType="logistic", maxIter=20, stepSize=0.1, seed=None):
         """
         setParams(self, featuresCol="features", labelCol="label", predictionCol="prediction", \
                   maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0, \
                   maxMemoryInMB=256, cacheNodeIds=False, checkpointInterval=10, \
-                  lossType="logistic", maxIter=20, stepSize=0.1)
+                  lossType="logistic", maxIter=20, stepSize=0.1, seed=None)
         Sets params for Gradient Boosted Tree Classification.
         """
         kwargs = self.setParams._input_kwargs

python/pyspark/ml/regression.py

@@ -641,7 +641,7 @@ class GBTRegressor(JavaEstimator, HasFeaturesCol, HasLabelCol, HasPredictionCol,
     >>> df = sqlContext.createDataFrame([
     ...     (1.0, Vectors.dense(1.0)),
     ...     (0.0, Vectors.sparse(1, [], []))], ["label", "features"])
-    >>> gbt = GBTRegressor(maxIter=5, maxDepth=2)
+    >>> gbt = GBTRegressor(maxIter=5, maxDepth=2, seed=42)
     >>> model = gbt.fit(df)
     >>> allclose(model.treeWeights, [1.0, 0.1, 0.1, 0.1, 0.1])
     True
@@ -664,18 +664,19 @@ class GBTRegressor(JavaEstimator, HasFeaturesCol, HasLabelCol, HasPredictionCol,
     def __init__(self, featuresCol="features", labelCol="label", predictionCol="prediction",
                  maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0,
                  maxMemoryInMB=256, cacheNodeIds=False, subsamplingRate=1.0,
-                 checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1):
+                 checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1, seed=None):
         """
         __init__(self, featuresCol="features", labelCol="label", predictionCol="prediction", \
                  maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0, \
                  maxMemoryInMB=256, cacheNodeIds=False, subsamplingRate=1.0, \
-                 checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1)
+                 checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1, seed=None)
         """
         super(GBTRegressor, self).__init__()
         self._java_obj = self._new_java_obj("org.apache.spark.ml.regression.GBTRegressor", self.uid)
         self._setDefault(maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0,
                          maxMemoryInMB=256, cacheNodeIds=False, subsamplingRate=1.0,
-                         checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1)
+                         checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1,
+                         seed=None)
         kwargs = self.__init__._input_kwargs
         self.setParams(**kwargs)
 
@@ -684,12 +685,12 @@ def __init__(self, featuresCol="features", labelCol="label", predictionCol="pred
     def setParams(self, featuresCol="features", labelCol="label", predictionCol="prediction",
                   maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0,
                   maxMemoryInMB=256, cacheNodeIds=False, subsamplingRate=1.0,
-                  checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1):
+                  checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1, seed=None):
         """
         setParams(self, featuresCol="features", labelCol="label", predictionCol="prediction", \
                   maxDepth=5, maxBins=32, minInstancesPerNode=1, minInfoGain=0.0, \
                   maxMemoryInMB=256, cacheNodeIds=False, subsamplingRate=1.0, \
-                  checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1)
+                  checkpointInterval=10, lossType="squared", maxIter=20, stepSize=0.1, seed=None)
         Sets params for Gradient Boosted Tree Regression.
         """
         kwargs = self.setParams._input_kwargs