Github user hirakendu commented on a diff in the pull request:
https://github.com/apache/spark/pull/79#discussion_r11229120
--- Diff:
mllib/src/main/scala/org/apache/spark/mllib/tree/model/Split.scala ---
@@ -0,0 +1,64 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
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+ * The ASF licenses this file to You under the Apache License, Version 2.0
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+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
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+ */
+
+package org.apache.spark.mllib.tree.model
+
+import org.apache.spark.mllib.tree.configuration.FeatureType.FeatureType
+
+/**
+ * Split applied to a feature
+ * @param feature feature index
+ * @param threshold threshold for continuous feature
+ * @param featureType type of feature -- categorical or continuous
+ * @param categories accepted values for categorical variables
+ */
+case class Split(
--- End diff --
The functionality of `Split` can be simplified by a modification. If I
understand correctly, `Split` represents the left or right (low or high) branch
of the parent node. Instead, it suffices to store the branching condition for
each node as a splitting condition. This can be appropriately named as
`SplitPredicate` or `SplittingCondition` or branching condition and consist of
feature id, feature type (continuous or categorical), threshold, left branch
categories and right branch categories.
I think depending on the choice here, we require `Filter`, but nonetheless
I think it's redundant and we should exploit the recursive/linked structure of
tree, which we are doing anyway.
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