1 files changed, 49 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/stat/ranking/NaNStrategy.java b/src/main/java/org/apache/commons/math/stat/ranking/NaNStrategy.java
new file mode 100644
index 0000000..cffa7d1
--- /dev/null
+++ b/src/main/java/org/apache/commons/math/stat/ranking/NaNStrategy.java
@@ -0,0 +1,49 @@
+/*
+ * 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.commons.math.stat.ranking;
+
+/**
+ * Strategies for handling NaN values in rank transformations.
+ * <ul>
+ * <li>MINIMAL - NaNs are treated as minimal in the ordering, equivalent to
+ * (that is, tied with) <code>Double.NEGATIVE_INFINITY</code>.</li>
+ * <li>MAXIMAL - NaNs are treated as maximal in the ordering, equivalent to
+ * <code>Double.POSITIVE_INFINITY</code></li>
+ * <li>REMOVED - NaNs are removed before the rank transform is applied</li>
+ * <li>FIXED - NaNs are left "in place," that is the rank transformation is
+ * applied to the other elements in the input array, but the NaN elements
+ * are returned unchanged.</li>
+ * </ul>
+ *
+ * @since 2.0
+ * @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $
+ */
+public enum NaNStrategy {
+
+    /** NaNs are considered minimal in the ordering */
+    MINIMAL,
+
+    /** NaNs are considered maximal in the ordering */
+    MAXIMAL,
+
+    /** NaNs are removed before computing ranks */
+    REMOVED,
+
+    /** NaNs are left in place */
+    FIXED
+}