1 /*
2 * Copyright (C) 2023 Alberto Irurueta Carro (alberto@irurueta.com)
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package com.irurueta.numerical.interpolation;
17
18 /**
19 * Computes linear interpolation.
20 */
21 public class LinearInterpolator extends BaseInterpolator {
22
23 /**
24 * Length of x's and y's to take into account.
25 */
26 private static final int M = 2;
27
28 public LinearInterpolator(final double[] x, final double[] y) {
29 super(x, y, M);
30 }
31
32 /**
33 * Actual interpolation method to be implemented by subclasses.
34 *
35 * @param j index where value x to be interpolated in located in the array of xx.
36 * @param x value to obtain interpolation for.
37 * @return interpolated value.
38 */
39 @Override
40 public double rawinterp(int j, double x) {
41 if (xx[j] == xx[j + 1]) {
42 return yy[j];
43 } else {
44 return yy[j] + ((x - xx[j]) / (xx[j + 1] - xx[j])) * (yy[j + 1] - yy[j]);
45 }
46 }
47 }