1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.statistics.ranking;
18
19 /**
20 * Strategies for handling {@link Double#NaN NaN} values in rank transformations.
21 *
22 * @since 1.1
23 */
24 public enum NaNStrategy {
25
26 /**
27 * NaNs are considered minimal in the ordering, equivalent to (that is, tied
28 * with) {@linkplain Double#NEGATIVE_INFINITY negative infinity}.
29 */
30 MINIMAL,
31
32 /**
33 * NaNs are considered maximal in the ordering, equivalent to (that is, tied
34 * with) {@linkplain Double#POSITIVE_INFINITY positive infinity}.
35 */
36 MAXIMAL,
37
38 /** NaNs are removed before rank transform is applied. */
39 REMOVED,
40
41 /**
42 * NaNs are left fixed "in place", that is the rank transformation is applied to
43 * the other elements in the input array, but the NaN elements are returned
44 * unchanged.
45 */
46 FIXED,
47
48 /** NaNs result in an exception. */
49 FAILED
50 }