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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.integration;
17  
18  import com.irurueta.numerical.SingleDimensionFunctionEvaluatorListener;
19  
20  /**
21   * Computes function integration by using an infinity mid-point quadrature.
22   * If you need to integrate from a negative lower limit to positive infinity, you do this by
23   * breaking the integral into two pieces at some positive value:
24   * InfinityMidPointQuadratureIntegrator integrator1 =
25   * new InfinityMidPointQuadratureIntegrator(-5.0, 2.0, listener);
26   * InfinityMidPointQuadratureIntegrator integrator2 =
27   * new InfinityMidPointQuadratureIntegrator(2.0, 1e99, listener);
28   * double integral = integrator1.integrate() + integrator2.integrate();
29   */
30  public class InfinityMidPointQuadratureIntegrator extends QuadratureIntegrator<InfinityMidPointQuadrature> {
31  
32      /**
33       * Constructor.
34       *
35       * @param a        Lower limit of integration.
36       * @param b        Upper limit of integration.
37       * @param listener listener to evaluate a single dimension function at required points.
38       * @param eps      required accuracy.
39       */
40      public InfinityMidPointQuadratureIntegrator(
41              final double a, final double b, final SingleDimensionFunctionEvaluatorListener listener, final double eps) {
42          super(new InfinityMidPointQuadrature(a, b, listener), eps);
43      }
44  
45      /**
46       * Constructor.
47       *
48       * @param a        Lower limit of integration.
49       * @param b        Upper limit of integration.
50       * @param listener listener to evaluate a single dimension function at required points.
51       */
52      public InfinityMidPointQuadratureIntegrator(
53              final double a, final double b, final SingleDimensionFunctionEvaluatorListener listener) {
54          this(a, b, listener, EPS);
55      }
56  
57      /**
58       * Gets type of quadrature.
59       *
60       * @return type of quadrature.
61       */
62      @Override
63      public QuadratureType getQuadratureType() {
64          return QuadratureType.INFINITY_MID_POINT;
65      }
66  }