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
18 package org.apache.commons.math4.legacy.stat.ranking;
19
20 /**
21 * Strategies for handling tied values in rank transformations.
22 * <ul>
23 * <li>SEQUENTIAL - Ties are assigned ranks in order of occurrence in the original array,
24 * for example (1,3,4,3) is ranked as (1,2,4,3)</li>
25 * <li>MINIMUM - Tied values are assigned the minimum applicable rank, or the rank
26 * of the first occurrence. For example, (1,3,4,3) is ranked as (1,2,4,2)</li>
27 * <li>MAXIMUM - Tied values are assigned the maximum applicable rank, or the rank
28 * of the last occurrence. For example, (1,3,4,3) is ranked as (1,3,4,3)</li>
29 * <li>AVERAGE - Tied values are assigned the average of the applicable ranks.
30 * For example, (1,3,4,3) is ranked as (1,2.5,4,2.5)</li>
31 * <li>RANDOM - Tied values are assigned a random integer rank from among the
32 * applicable values. The assigned rank will always be an integer, (inclusively)
33 * between the values returned by the MINIMUM and MAXIMUM strategies.</li>
34 * </ul>
35 *
36 * @since 2.0
37 */
38 public enum TiesStrategy {
39
40 /** Ties assigned sequential ranks in order of occurrence. */
41 SEQUENTIAL,
42
43 /** Ties get the minimum applicable rank. */
44 MINIMUM,
45
46 /** Ties get the maximum applicable rank. */
47 MAXIMUM,
48
49 /** Ties get the average of applicable ranks. */
50 AVERAGE,
51
52 /** Ties get a random integral value from among applicable ranks. */
53 RANDOM
54 }