001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.math.stat.ranking; 019 020 /** 021 * Strategies for handling NaN values in rank transformations. 022 * <ul> 023 * <li>MINIMAL - NaNs are treated as minimal in the ordering, equivalent to 024 * (that is, tied with) <code>Double.NEGATIVE_INFINITY</code>.</li> 025 * <li>MAXIMAL - NaNs are treated as maximal in the ordering, equivalent to 026 * <code>Double.POSITIVE_INFINITY</code></li> 027 * <li>REMOVED - NaNs are removed before the rank transform is applied</li> 028 * <li>FIXED - NaNs are left "in place," that is the rank transformation is 029 * applied to the other elements in the input array, but the NaN elements 030 * are returned unchanged.</li> 031 * </ul> 032 * 033 * @since 2.0 034 * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $ 035 */ 036 public enum NaNStrategy { 037 038 /** NaNs are considered minimal in the ordering */ 039 MINIMAL, 040 041 /** NaNs are considered maximal in the ordering */ 042 MAXIMAL, 043 044 /** NaNs are removed before computing ranks */ 045 REMOVED, 046 047 /** NaNs are left in place */ 048 FIXED 049 }