LZ9.h
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1 //===========================================================================
2 /*!
3  *
4  *
5  * \brief Multi-objective optimization benchmark function LZ9.
6  *
7  * The function is described in
8  *
9  * H. Li and Q. Zhang.
10  * Multiobjective Optimization Problems with Complicated Pareto Sets, MOEA/D and NSGA-II,
11  * IEEE Trans on Evolutionary Computation, 2(12):284-302, April 2009.
12  *
13  *
14  *
15  * \author -
16  * \date -
17  *
18  *
19  * \par Copyright 1995-2017 Shark Development Team
20  *
21  * <BR><HR>
22  * This file is part of Shark.
23  * <http://shark-ml.org/>
24  *
25  * Shark is free software: you can redistribute it and/or modify
26  * it under the terms of the GNU Lesser General Public License as published
27  * by the Free Software Foundation, either version 3 of the License, or
28  * (at your option) any later version.
29  *
30  * Shark is distributed in the hope that it will be useful,
31  * but WITHOUT ANY WARRANTY; without even the implied warranty of
32  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
33  * GNU Lesser General Public License for more details.
34  *
35  * You should have received a copy of the GNU Lesser General Public License
36  * along with Shark. If not, see <http://www.gnu.org/licenses/>.
37  *
38  */
39 //===========================================================================
40 #ifndef SHARK_OBJECTIVEFUNCTIONS_BENCHMARK_LZ9_H
41 #define SHARK_OBJECTIVEFUNCTIONS_BENCHMARK_LZ9_H
42 
45 
46 namespace shark {
47 struct LZ9 : public MultiObjectiveFunction
48 {
49  LZ9(std::size_t numVariables = 0) : m_handler(SearchPointType(numVariables,0),SearchPointType(numVariables,1) ){
50  announceConstraintHandler(&m_handler);
51  }
52 
53  /// \brief From INameable: return the class name.
54  std::string name() const
55  { return "LZ9"; }
56 
57  std::size_t numberOfObjectives()const{
58  return 2;
59  }
60 
61  std::size_t numberOfVariables()const{
62  return m_handler.dimensions();
63  }
64 
66  return true;
67  }
68 
69  /// \brief Adjusts the number of variables if the function is scalable.
70  /// \param [in] numberOfVariables The new dimension.
72  SearchPointType lb(numberOfVariables,-1);
73  SearchPointType ub(numberOfVariables, 1);
74  lb(0) = 0;
75  ub(0) = 1;
76  m_handler.setBounds(lb, ub);
77  }
78 
79  ResultType eval( const SearchPointType & x ) const {
81 
82  ResultType value( numberOfObjectives() );
83 
84  std::size_t counter1 = 0, counter2 = 0;
85  for( std::size_t i = 1; i < x.size(); i++ ) {
86  if( i % 2 == 0 ) {
87  counter2++;
88  value[1] += sqr( x(i) - ::sin( 6 * M_PI * x( 0 ) + i*M_PI/x.size() ) );
89  } else {
90  counter1++;
91  value[0] += sqr( x(i) - ::sin( 6 * M_PI * x( 0 ) + i*M_PI/x.size() ) );
92  }
93  }
94 
95  value[0] *= 2./counter1;
96  value[0] += x( 0 );
97 
98  value[1] *= 2./counter2;
99  value[1] += 1 - x( 0 ) * x( 0 );
100 
101  return( value );
102  }
103 private:
105 };
106 
107 }
108 #endif