From 595ae211e25babebe2aadc250ef5edf596c91f78 Mon Sep 17 00:00:00 2001
From: Ryan Curtin <ryan@ratml.org>
Date: Thu, 5 Feb 2015 15:31:38 -0500
Subject: [PATCH] Try to keep the query and reference levels equal.

---
 .../core/tree/binary_space_tree/dual_tree_traverser_impl.hpp  | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/mlpack/core/tree/binary_space_tree/dual_tree_traverser_impl.hpp b/src/mlpack/core/tree/binary_space_tree/dual_tree_traverser_impl.hpp
index 1a1d35348f..a226cc022d 100644
--- a/src/mlpack/core/tree/binary_space_tree/dual_tree_traverser_impl.hpp
+++ b/src/mlpack/core/tree/binary_space_tree/dual_tree_traverser_impl.hpp
@@ -67,7 +67,9 @@ DualTreeTraverser<RuleType>::Traverse(
       numBaseCases += referenceNode.Count();
     }
   }
-  else if ((!queryNode.IsLeaf()) && referenceNode.IsLeaf())
+  else if (((!queryNode.IsLeaf()) && referenceNode.IsLeaf()) ||
+           (queryNode.NumDescendants() > 3 * referenceNode.NumDescendants() &&
+            !queryNode.IsLeaf() && !referenceNode.IsLeaf()))
   {
     // We have to recurse down the query node.  In this case the recursion order
     // does not matter.