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 * Interface representing a rank transformation.
22 *
23 * @since 2.0
24 */
25 public interface RankingAlgorithm {
26 /**
27 * <p>Performs a rank transformation on the input data, returning an array
28 * of ranks.</p>
29 *
30 * <p>Ranks should be 1-based - that is, the smallest value
31 * returned in an array of ranks should be greater than or equal to one,
32 * rather than 0. Ranks should in general take integer values, though
33 * implementations may return averages or other floating point values
34 * to resolve ties in the input data.</p>
35 *
36 * @param data array of data to be ranked
37 * @return an array of ranks corresponding to the elements of the input array
38 */
39 double[] rank (double[] data);
40 }