[mlpack-git] master: Add test: equally good features should not split. (2d5fb03)

[gitdub at big.cc.gt.atl.ga.us]

Repository : https://github.com/mlpack/mlpack

On branch  : master
Link       : https://github.com/mlpack/mlpack/compare/de9cc4b05069e1fa4793d9355f2f595af5ff45d2...6070527af14296cd99739de6c62666cc5d2a2125

>---------------------------------------------------------------

commit 2d5fb03f82e5fc8eaa7b999015c7ef8a8402bbdd
Author: ryan <ryan at ratml.org>
Date:   Thu Sep 24 11:03:13 2015 -0400

    Add test: equally good features should not split.


>---------------------------------------------------------------

2d5fb03f82e5fc8eaa7b999015c7ef8a8402bbdd
 src/mlpack/tests/hoeffding_tree_test.cpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/mlpack/tests/hoeffding_tree_test.cpp b/src/mlpack/tests/hoeffding_tree_test.cpp
index d34f945..0bab98d 100644
--- a/src/mlpack/tests/hoeffding_tree_test.cpp
+++ b/src/mlpack/tests/hoeffding_tree_test.cpp
@@ -348,6 +348,32 @@ BOOST_AUTO_TEST_CASE(HoeffdingSplitAlmostPerfectSplit)
 }
 
 /**
+ * Test that the HoeffdingSplit class will not split if the two features are
+ * equally good.
+ */
+BOOST_AUTO_TEST_CASE(HoeffdingSplitEqualSplitTest)
+{
+  // Two categories and two dimensions.
+  data::DatasetInfo info;
+  info.MapString("cat0", 0);
+  info.MapString("cat1", 0);
+  info.MapString("cat0", 1);
+  info.MapString("cat1", 1);
+
+  HoeffdingSplit<> split(2, 2, info, 0.95);
+
+  // Feed samples.
+  for (size_t i = 0; i < 500; ++i)
+  {
+    split.Train(arma::Col<size_t>("0 0"), 0);
+    split.Train(arma::Col<size_t>("1 1"), 1);
+  }
+
+  // Ensure that splitting should not happen.
+  BOOST_REQUIRE_EQUAL(split.SplitCheck(), 0);
+}
+
+/**
  * Build a decision tree on a dataset with two meaningless dimensions and ensure
  * that it can properly classify all of the training points.  (The dataset is
  * perfectly separable.)