Github user jkbradley commented on a diff in the pull request:
https://github.com/apache/spark/pull/12050#discussion_r58777001
--- Diff:
mllib/src/test/scala/org/apache/spark/ml/tree/impl/GradientBoostedTreesSuite.scala
---
@@ -0,0 +1,83 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.ml.tree.impl
+
+import org.apache.spark.SparkFunSuite
+import org.apache.spark.internal.Logging
+import org.apache.spark.mllib.regression.LabeledPoint
+import org.apache.spark.mllib.tree.{GradientBoostedTreesSuite =>
OldGBTSuite}
+import org.apache.spark.mllib.tree.configuration.{BoostingStrategy,
Strategy}
+import org.apache.spark.mllib.tree.configuration.Algo._
+import org.apache.spark.mllib.tree.impurity.Variance
+import org.apache.spark.mllib.tree.loss.{AbsoluteError, LogLoss,
SquaredError}
+import org.apache.spark.mllib.util.MLlibTestSparkContext
+
+/**
+ * Test suite for [[GradientBoostedTrees]].
+ */
+class GradientBoostedTreesSuite extends SparkFunSuite with
MLlibTestSparkContext with Logging {
+
+ test("runWithValidation stops early and performs better on a validation
dataset") {
+ // Set numIterations large enough so that it stops early.
+ val numIterations = 20
+ val trainRdd = sc.parallelize(OldGBTSuite.trainData, 2)
+ val validateRdd = sc.parallelize(OldGBTSuite.validateData, 2)
+ val trainDF = sqlContext.createDataFrame(trainRdd)
+ val validateDF = sqlContext.createDataFrame(validateRdd)
+
+ val algos = Array(Regression, Regression, Classification)
+ val losses = Array(SquaredError, AbsoluteError, LogLoss)
+ algos.zip(losses).foreach { case (algo, loss) =>
+ val treeStrategy = new Strategy(algo = algo, impurity = Variance,
maxDepth = 2,
+ categoricalFeaturesInfo = Map.empty)
+ val boostingStrategy =
+ new BoostingStrategy(treeStrategy, loss, numIterations,
validationTol = 0.0)
+ val (validateTrees, validateTreeWeights) = GradientBoostedTrees
+ .runWithValidation(trainRdd, validateRdd, boostingStrategy, 42L)
+ val numTrees = validateTrees.length
+ assert(numTrees !== numIterations)
+
+ // Test that it performs better on the validation dataset.
+ val (trees, treeWeights) = GradientBoostedTrees.run(trainRdd,
boostingStrategy, 42L)
+ val (errorWithoutValidation, errorWithValidation) = {
+ if (algo == Classification) {
+ val remappedRdd = validateRdd.map(x => new LabeledPoint(2 *
x.label - 1, x.features))
+ (GradientBoostedTrees.computeError(remappedRdd, trees,
treeWeights, loss),
+ GradientBoostedTrees.computeError(remappedRdd, trees,
treeWeights, loss))
+ } else {
+ (GradientBoostedTrees.computeError(validateRdd, trees,
treeWeights, loss),
+ GradientBoostedTrees.computeError(validateRdd, trees,
treeWeights, loss))
--- End diff --
trees --> validateTrees
same for treeWeights
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