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.math4.legacy.analysis;
18
19 import org.apache.commons.math4.legacy.analysis.function.Sinc;
20
21 /**
22 * Auxiliary class for testing optimizers.
23 *
24 */
25 public class SumSincFunction implements MultivariateFunction {
26 private static final UnivariateFunction sinc = new Sinc();
27
28 /**
29 * Factor that will multiply each term of the sum.
30 */
31 private final double factor;
32
33 /**
34 * @param factor Factor that will multiply each term of the sum.
35 */
36 public SumSincFunction(double factor) {
37 this.factor = factor;
38 }
39
40 /**
41 * @param point Argument.
42 * @return the value of this function at point {@code x}.
43 */
44 @Override
45 public double value(double[] point) {
46 double sum = 0;
47 for (int i = 0, max = point.length; i < max; i++) {
48 final double x = point[i];
49 final double v = sinc.value(x);
50 sum += v;
51 }
52 return factor * sum;
53 }
54 }