[SPARK-7333] [MLLIB] Add BinaryClassificationEvaluator to PySpark

This PR adds `BinaryClassificationEvaluator` to Python ML Pipelines API, which is a simple wrapper of the Scala implementation. oefirouz

Author: Xiangrui Meng <meng@databricks.com>

Closes #5885 from mengxr/SPARK-7333 and squashes the following commits:

25d7451 [Xiangrui Meng] fix tests in python 3
babdde7 [Xiangrui Meng] fix doc
cb51e6a [Xiangrui Meng] add BinaryClassificationEvaluator in PySpark

1 files changed, 107 insertions, 0 deletions

diff --git a/python/pyspark/ml/evaluation.py b/python/pyspark/ml/evaluation.py
new file mode 100644
index 0000000000..02020ebff9
--- /dev/null
+++ b/python/pyspark/ml/evaluation.py
@@ -0,0 +1,107 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from pyspark.ml.wrapper import JavaEvaluator
+from pyspark.ml.param import Param, Params
+from pyspark.ml.param.shared import HasLabelCol, HasRawPredictionCol
+from pyspark.ml.util import keyword_only
+from pyspark.mllib.common import inherit_doc
+
+__all__ = ['BinaryClassificationEvaluator']
+
+
+@inherit_doc
+class BinaryClassificationEvaluator(JavaEvaluator, HasLabelCol, HasRawPredictionCol):
+    """
+    Evaluator for binary classification, which expects two input
+    columns: rawPrediction and label.
+
+    >>> from pyspark.mllib.linalg import Vectors
+    >>> scoreAndLabels = map(lambda x: (Vectors.dense([1.0 - x[0], x[0]]), x[1]),
+    ...    [(0.1, 0.0), (0.1, 1.0), (0.4, 0.0), (0.6, 0.0), (0.6, 1.0), (0.6, 1.0), (0.8, 1.0)])
+    >>> dataset = sqlContext.createDataFrame(scoreAndLabels, ["raw", "label"])
+    ...
+    >>> evaluator = BinaryClassificationEvaluator(rawPredictionCol="raw")
+    >>> evaluator.evaluate(dataset)
+    0.70...
+    >>> evaluator.evaluate(dataset, {evaluator.metricName: "areaUnderPR"})
+    0.83...
+    """
+
+    _java_class = "org.apache.spark.ml.evaluation.BinaryClassificationEvaluator"
+
+    # a placeholder to make it appear in the generated doc
+    metricName = Param(Params._dummy(), "metricName",
+                       "metric name in evaluation (areaUnderROC|areaUnderPR)")
+
+    @keyword_only
+    def __init__(self, rawPredictionCol="rawPrediction", labelCol="label",
+                 metricName="areaUnderROC"):
+        """
+        __init__(self, rawPredictionCol="rawPrediction", labelCol="label", \
+                 metricName="areaUnderROC")
+        """
+        super(BinaryClassificationEvaluator, self).__init__()
+        #: param for metric name in evaluation (areaUnderROC|areaUnderPR)
+        self.metricName = Param(self, "metricName",
+                                "metric name in evaluation (areaUnderROC|areaUnderPR)")
+        self._setDefault(rawPredictionCol="rawPrediction", labelCol="label",
+                         metricName="areaUnderROC")
+        kwargs = self.__init__._input_kwargs
+        self._set(**kwargs)
+
+    def setMetricName(self, value):
+        """
+        Sets the value of :py:attr:`metricName`.
+        """
+        self.paramMap[self.metricName] = value
+        return self
+
+    def getMetricName(self):
+        """
+        Gets the value of metricName or its default value.
+        """
+        return self.getOrDefault(self.metricName)
+
+    @keyword_only
+    def setParams(self, rawPredictionCol="rawPrediction", labelCol="label",
+                  metricName="areaUnderROC"):
+        """
+        setParams(self, rawPredictionCol="rawPrediction", labelCol="label", \
+                  metricName="areaUnderROC")
+        Sets params for binary classification evaluator.
+        """
+        kwargs = self.setParams._input_kwargs
+        return self._set(**kwargs)
+
+
+if __name__ == "__main__":
+    import doctest
+    from pyspark.context import SparkContext
+    from pyspark.sql import SQLContext
+    globs = globals().copy()
+    # The small batch size here ensures that we see multiple batches,
+    # even in these small test examples:
+    sc = SparkContext("local[2]", "ml.evaluation tests")
+    sqlContext = SQLContext(sc)
+    globs['sc'] = sc
+    globs['sqlContext'] = sqlContext
+    (failure_count, test_count) = doctest.testmod(
+        globs=globs, optionflags=doctest.ELLIPSIS)
+    sc.stop()
+    if failure_count:
+        exit(-1)