Author: adeneche
Date: Fri Dec 23 07:30:28 2011
New Revision: 1222595
URL: http://svn.apache.org/viewvc?rev=1222595&view=rev
Log:
MAHOUT-840 DecisionTreeBuilder Test
Added:
mahout/trunk/core/src/test/java/org/apache/mahout/classifier/df/builder/DecisionTreeBuilderTest.java
Added:
mahout/trunk/core/src/test/java/org/apache/mahout/classifier/df/builder/DecisionTreeBuilderTest.java
URL:
http://svn.apache.org/viewvc/mahout/trunk/core/src/test/java/org/apache/mahout/classifier/df/builder/DecisionTreeBuilderTest.java?rev=1222595&view=auto
==============================================================================
---
mahout/trunk/core/src/test/java/org/apache/mahout/classifier/df/builder/DecisionTreeBuilderTest.java
(added)
+++
mahout/trunk/core/src/test/java/org/apache/mahout/classifier/df/builder/DecisionTreeBuilderTest.java
Fri Dec 23 07:30:28 2011
@@ -0,0 +1,78 @@
+/**
+ * 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.mahout.classifier.df.builder;
+
+import java.lang.reflect.Method;
+import java.util.Random;
+import java.util.Arrays;
+
+import org.apache.commons.lang.ArrayUtils;
+import org.apache.mahout.common.MahoutTestCase;
+import org.apache.mahout.common.RandomUtils;
+import org.junit.Test;
+
+public final class DecisionTreeBuilderTest extends MahoutTestCase {
+
+ /**
+ * make sure that DecisionTreeBuilder.randomAttributes() returns the correct
number of attributes, that have not been
+ * selected yet
+ */
+ @Test
+ public void testRandomAttributes() throws Exception {
+ Random rng = RandomUtils.getRandom();
+ int nbAttributes = rng.nextInt(100) + 1;
+ boolean[] selected = new boolean[nbAttributes];
+
+ for (int nloop = 0; nloop < 100; nloop++) {
+ Arrays.fill(selected, false);
+
+ // randomly select some attributes
+ int nbSelected = rng.nextInt(nbAttributes - 1);
+ for (int index = 0; index < nbSelected; index++) {
+ int attr;
+ do {
+ attr = rng.nextInt(nbAttributes);
+ } while (selected[attr]);
+
+ selected[attr] = true;
+ }
+
+ int m = rng.nextInt(nbAttributes);
+
+ Method randomAttributes =
DecisionTreeBuilder.class.getDeclaredMethod("randomAttributes",
+ Random.class, boolean[].class, int.class);
+ randomAttributes.setAccessible(true);
+ int[] attrs = (int[]) randomAttributes.invoke(null, rng, selected, m);
+
+ assertNotNull(attrs);
+ assertEquals(Math.min(m, nbAttributes - nbSelected), attrs.length);
+
+ for (int attr : attrs) {
+ // the attribute should not be already selected
+ assertFalse("an attribute has already been selected", selected[attr]);
+
+ // each attribute should be in the range [0, nbAttributes[
+ assertTrue(attr >= 0);
+ assertTrue(attr < nbAttributes);
+
+ // each attribute should appear only once
+ assertEquals(ArrayUtils.indexOf(attrs, attr),
ArrayUtils.lastIndexOf(attrs, attr));
+ }
+ }
+ }
+}
