1 files changed, 1 insertions, 113 deletions

diff --git a/mllib/src/main/scala/org/apache/spark/ml/tree/impl/RandomForest.scala b/mllib/src/main/scala/org/apache/spark/ml/tree/impl/RandomForest.scala
index 7774ae64e5..7b1fd089f2 100644
--- a/mllib/src/main/scala/org/apache/spark/ml/tree/impl/RandomForest.scala
+++ b/mllib/src/main/scala/org/apache/spark/ml/tree/impl/RandomForest.scala
@@ -26,16 +26,12 @@ import org.apache.spark.internal.Logging
 import org.apache.spark.ml.classification.DecisionTreeClassificationModel
 import org.apache.spark.ml.regression.DecisionTreeRegressionModel
 import org.apache.spark.ml.tree._
-import org.apache.spark.mllib.linalg.{Vector, Vectors}
 import org.apache.spark.mllib.regression.LabeledPoint
 import org.apache.spark.mllib.tree.configuration.{Algo => OldAlgo, Strategy => OldStrategy}
-import org.apache.spark.mllib.tree.impl.{BaggedPoint, DecisionTreeMetadata, DTStatsAggregator,
-  TimeTracker}
 import org.apache.spark.mllib.tree.impurity.ImpurityCalculator
 import org.apache.spark.mllib.tree.model.ImpurityStats
 import org.apache.spark.rdd.RDD
 import org.apache.spark.storage.StorageLevel
-import org.apache.spark.util.collection.OpenHashMap
 import org.apache.spark.util.random.{SamplingUtils, XORShiftRandom}
 
 
@@ -332,7 +328,7 @@ private[spark] object RandomForest extends Logging {
   /**
    * Given a group of nodes, this finds the best split for each node.
    *
-   * @param input Training data: RDD of [[org.apache.spark.mllib.tree.impl.TreePoint]]
+   * @param input Training data: RDD of [[org.apache.spark.ml.tree.impl.TreePoint]]
    * @param metadata Learning and dataset metadata
    * @param topNodes Root node for each tree.  Used for matching instances with nodes.
    * @param nodesForGroup Mapping: treeIndex --> nodes to be split in tree
@@ -1105,112 +1101,4 @@ private[spark] object RandomForest extends Logging {
     }
   }
 
-  /**
-   * Given a Random Forest model, compute the importance of each feature.
-   * This generalizes the idea of "Gini" importance to other losses,
-   * following the explanation of Gini importance from "Random Forests" documentation
-   * by Leo Breiman and Adele Cutler, and following the implementation from scikit-learn.
-   *
-   * This feature importance is calculated as follows:
-   *  - Average over trees:
-   *     - importance(feature j) = sum (over nodes which split on feature j) of the gain,
-   *       where gain is scaled by the number of instances passing through node
-   *     - Normalize importances for tree to sum to 1.
-   *  - Normalize feature importance vector to sum to 1.
-   *
-   * @param trees  Unweighted forest of trees
-   * @param numFeatures  Number of features in model (even if not all are explicitly used by
-   *                     the model).
-   *                     If -1, then numFeatures is set based on the max feature index in all trees.
-   * @return  Feature importance values, of length numFeatures.
-   */
-  private[ml] def featureImportances(trees: Array[DecisionTreeModel], numFeatures: Int): Vector = {
-    val totalImportances = new OpenHashMap[Int, Double]()
-    trees.foreach { tree =>
-      // Aggregate feature importance vector for this tree
-      val importances = new OpenHashMap[Int, Double]()
-      computeFeatureImportance(tree.rootNode, importances)
-      // Normalize importance vector for this tree, and add it to total.
-      // TODO: In the future, also support normalizing by tree.rootNode.impurityStats.count?
-      val treeNorm = importances.map(_._2).sum
-      if (treeNorm != 0) {
-        importances.foreach { case (idx, impt) =>
-          val normImpt = impt / treeNorm
-          totalImportances.changeValue(idx, normImpt, _ + normImpt)
-        }
-      }
-    }
-    // Normalize importances
-    normalizeMapValues(totalImportances)
-    // Construct vector
-    val d = if (numFeatures != -1) {
-      numFeatures
-    } else {
-      // Find max feature index used in trees
-      val maxFeatureIndex = trees.map(_.maxSplitFeatureIndex()).max
-      maxFeatureIndex + 1
-    }
-    if (d == 0) {
-      assert(totalImportances.size == 0, s"Unknown error in computing feature" +
-        s" importance: No splits found, but some non-zero importances.")
-    }
-    val (indices, values) = totalImportances.iterator.toSeq.sortBy(_._1).unzip
-    Vectors.sparse(d, indices.toArray, values.toArray)
-  }
-
-  /**
-   * Given a Decision Tree model, compute the importance of each feature.
-   * This generalizes the idea of "Gini" importance to other losses,
-   * following the explanation of Gini importance from "Random Forests" documentation
-   * by Leo Breiman and Adele Cutler, and following the implementation from scikit-learn.
-   *
-   * This feature importance is calculated as follows:
-   *  - importance(feature j) = sum (over nodes which split on feature j) of the gain,
-   *    where gain is scaled by the number of instances passing through node
-   *  - Normalize importances for tree to sum to 1.
-   *
-   * @param tree  Decision tree to compute importances for.
-   * @param numFeatures  Number of features in model (even if not all are explicitly used by
-   *                     the model).
-   *                     If -1, then numFeatures is set based on the max feature index in all trees.
-   * @return  Feature importance values, of length numFeatures.
-   */
-  private[ml] def featureImportances(tree: DecisionTreeModel, numFeatures: Int): Vector = {
-    featureImportances(Array(tree), numFeatures)
-  }
-
-  /**
-   * Recursive method for computing feature importances for one tree.
-   * This walks down the tree, adding to the importance of 1 feature at each node.
-   * @param node  Current node in recursion
-   * @param importances  Aggregate feature importances, modified by this method
-   */
-  private[impl] def computeFeatureImportance(
-      node: Node,
-      importances: OpenHashMap[Int, Double]): Unit = {
-    node match {
-      case n: InternalNode =>
-        val feature = n.split.featureIndex
-        val scaledGain = n.gain * n.impurityStats.count
-        importances.changeValue(feature, scaledGain, _ + scaledGain)
-        computeFeatureImportance(n.leftChild, importances)
-        computeFeatureImportance(n.rightChild, importances)
-      case n: LeafNode =>
-        // do nothing
-    }
-  }
-
-  /**
-   * Normalize the values of this map to sum to 1, in place.
-   * If all values are 0, this method does nothing.
-   * @param map  Map with non-negative values.
-   */
-  private[impl] def normalizeMapValues(map: OpenHashMap[Int, Double]): Unit = {
-    val total = map.map(_._2).sum
-    if (total != 0) {
-      val keys = map.iterator.map(_._1).toArray
-      keys.foreach { key => map.changeValue(key, 0.0, _ / total) }
-    }
-  }
-
 }