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.numbers.angle;
18
19 import java.util.function.DoubleUnaryOperator;
20
21 /**
22 * Reduces {@code |a - offset|} to the primary interval {@code [0, |period|)}.
23 *
24 * Specifically, the {@link #applyAsDouble(double) computed value} is:
25 * {@code a - |period| * floor((a - offset) / |period|) - offset}.
26 */
27 public class Reduce implements DoubleUnaryOperator {
28 /** Offset. */
29 private final double offset;
30 /** Period. */
31 private final double period;
32
33 /**
34 * @param offset Value that will be mapped to {@code 0}.
35 * @param period Period.
36 */
37 public Reduce(double offset,
38 double period) {
39 this.offset = offset;
40 this.period = Math.abs(period);
41 }
42
43 /** {@inheritDoc} */
44 @Override
45 public double applyAsDouble(double x) {
46 final double xMo = x - offset;
47 return xMo - period * Math.floor(xMo / period);
48 }
49 }