DTLZ3.h
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1 //===========================================================================
2 /*!
3  *
4  *
5  * \brief Objective function DTLZ3.
6  *
7  *
8  *
9  * \author T.Voss, T. Glasmachers, O.Krause
10  * \date 2010-2011
11  *
12  *
13  * \par Copyright 1995-2017 Shark Development Team
14  *
15  * <BR><HR>
16  * This file is part of Shark.
17  * <http://shark-ml.org/>
18  *
19  * Shark is free software: you can redistribute it and/or modify
20  * it under the terms of the GNU Lesser General Public License as published
21  * by the Free Software Foundation, either version 3 of the License, or
22  * (at your option) any later version.
23  *
24  * Shark is distributed in the hope that it will be useful,
25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27  * GNU Lesser General Public License for more details.
28  *
29  * You should have received a copy of the GNU Lesser General Public License
30  * along with Shark. If not, see <http://www.gnu.org/licenses/>.
31  *
32  */
33 //===========================================================================
34 #ifndef SHARK_OBJECTIVEFUNCTIONS_BENCHMARK_DTLZ3_H
35 #define SHARK_OBJECTIVEFUNCTIONS_BENCHMARK_DTLZ3_H
36 
39 
40 namespace shark {
41 /**
42 * \brief Implements the benchmark function DTLZ3.
43 *
44 * See: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.18.7531&rep=rep1&type=pdf
45 * The benchmark function exposes the following features:
46 * - Scalable w.r.t. the searchspace and w.r.t. the objective space.
47 */
49 {
50  DTLZ3(std::size_t numVariables = 0) : m_objectives(2), m_handler(SearchPointType(numVariables,0),SearchPointType(numVariables,1) ){
51  announceConstraintHandler(&m_handler);
52  }
53 
54  /// \brief From INameable: return the class name.
55  std::string name() const
56  { return "DTLZ3"; }
57 
58  std::size_t numberOfObjectives()const{
59  return m_objectives;
60  }
61  bool hasScalableObjectives()const{
62  return true;
63  }
65  m_objectives = numberOfObjectives;
66  }
67 
68  std::size_t numberOfVariables()const{
69  return m_handler.dimensions();
70  }
71 
73  return true;
74  }
75 
76  /// \brief Adjusts the number of variables if the function is scalable.
77  /// \param [in] numberOfVariables The new dimension.
79  m_handler.setBounds(
80  SearchPointType(numberOfVariables,0),
81  SearchPointType(numberOfVariables,1)
82  );
83  }
84 
85  ResultType eval( const SearchPointType & x ) const {
87 
88  ResultType value( numberOfObjectives() );
89 
90  std::size_t k = numberOfVariables() - numberOfObjectives()+1;
91  double g = (double)k;
92  for( std::size_t i = numberOfVariables() - k; i < numberOfVariables(); i++ )
93  g += sqr( x( i ) - 0.5 ) - std::cos( 20.0 * M_PI * ( x( i ) - 0.5) );
94  g *= 100;
95 
96  for (std::size_t i = 0; i < numberOfObjectives(); i++) {
97  value[i] = 1.0+g;
98  for( std::size_t j = 0; j < numberOfObjectives() - i -1; ++j)
99  value[i] *= std::cos(x( j ) * M_PI / 2.0);
100 
101  if (i > 0)
102  value[i] *= std::sin(x(numberOfObjectives() - i -1) * M_PI / 2.0);
103  }
104 
105  return value;
106  }
107 private:
108  std::size_t m_objectives;
110 };
111 
112 }
113 #endif