View Javadoc
1   /*
2    * Licensed to the Hipparchus project 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 Hipparchus project 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    *      https://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.hipparchus.optim.nonlinear.vector.constrained;
18  
19  import org.hipparchus.linear.MatrixUtils;
20  import org.hipparchus.linear.RealMatrix;
21  import org.hipparchus.linear.RealVector;
22  import org.junit.jupiter.api.Test;
23  
24  import static org.junit.jupiter.api.Assertions.assertEquals;
25  
26  class TwiceDifferentiableFunctionTest {
27  
28      @Test
29      void testValue() {
30          // GIVEN
31          final double[] x = new double[] { 2. };
32          final TestTwiceDifferentiableFunction function = new TestTwiceDifferentiableFunction();
33          // WHEN
34          final double actualValue = function.value(x);
35          // THEN
36          final double expectedValueElement = x[0];
37          assertEquals(expectedValueElement, actualValue, 0);
38      }
39  
40      @Test
41      void testGradient() {
42          // GIVEN
43          final double[] x = new double[] { 2. };
44          final TestTwiceDifferentiableFunction function = new TestTwiceDifferentiableFunction();
45          // WHEN
46          final RealVector actualGradient = function.gradient(x);
47          // THEN
48          final double expectedValueElement = 1.;
49          assertEquals(expectedValueElement, actualGradient.getEntry(0), 0);
50      }
51  
52      @Test
53      void testHessian() {
54          // GIVEN
55          final double[] x = new double[] { 2. };
56          final TestTwiceDifferentiableFunction function = new TestTwiceDifferentiableFunction();
57          // WHEN
58          final RealMatrix actualGradient = function.hessian(x);
59          // THEN
60          final double expectedValueElement = 0.;
61          assertEquals(expectedValueElement, actualGradient.getEntry(0, 0), 0);
62      }
63  
64      private static class TestTwiceDifferentiableFunction extends TwiceDifferentiableFunction {
65  
66          @Override
67          public int dim() {
68              return 1;
69          }
70  
71          @Override
72          public double value(RealVector x) {
73              return x.getEntry(0);
74          }
75  
76          @Override
77          public RealVector gradient(RealVector x) {
78              return MatrixUtils.createRealVector(new double[] { 1. });
79          }
80  
81          @Override
82          public RealMatrix hessian(RealVector x) {
83              return MatrixUtils.createRealMatrix(1, 1);
84          }
85  
86      }
87  
88  }