PaGMO  1.1.5
ackley.cpp
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24 
25 #include <boost/math/constants/constants.hpp>
26 #include <cmath>
27 #include <string>
28 
29 
30 #include "../exceptions.h"
31 #include "../types.h"
32 #include "base.h"
33 #include "ackley.h"
34 
35 namespace pagmo { namespace problem {
36 
38 
46 {
47  // Set bounds.
48  set_lb(-15.0);
49  set_ub(30);
50 
51  // Initialise global minima vector vector vector vector
52  std::vector<decision_vector> best_x(1);
53  // The Ackley problem has only one global minimum: at (0, ..., 0)
54  // (the value for all dimensions is 0).
55  for(int i = 0; i < n; ++i) {
56  best_x[0].push_back(0);
57  }
58 
59  set_best_x(best_x);
60 }
61 
64 {
65  return base_ptr(new ackley(*this));
66 }
67 
70 {
71  pagmo_assert(f.size() == 1);
72  std::vector<double>::size_type n = x.size();
73  f[0]=0;
74 
75  double omega = 2.0 * M_PI;
76  double s1=0.0, s2=0.0;
77  double nepero=exp(1.0);
78 
79  for (std::vector<double>::size_type i=0; i<n; i++){
80  s1 += x[i]*x[i];
81  s2 += cos(omega*x[i]);
82  }
83  f[0] = -20*exp(-0.2 * sqrt(1.0/n * s1))-exp(1.0/n*s2)+ 20 + nepero;
84 }
85 
86 std::string ackley::get_name() const
87 {
88  return "Ackley";
89 }
90 
91 }}
92 
93 BOOST_CLASS_EXPORT_IMPLEMENT(pagmo::problem::ackley)
Root PaGMO namespace.
boost::shared_ptr< base > base_ptr
Alias for shared pointer to base problem.
Definition: problem/base.h:62
std::vector< double > decision_vector
Decision vector type.
Definition: types.h:40
std::string get_name() const
Get problem's name.
Definition: ackley.cpp:86
ackley(int=1)
Constructor from dimension.
Definition: ackley.cpp:45
void set_best_x(const std::vector< decision_vector > &)
Sets the best known decision vectors.
Base problem class.
Definition: problem/base.h:148
base_ptr clone() const
Clone method.
Definition: ackley.cpp:63
void set_lb(const decision_vector &)
Set lower bounds from pagmo::decision_vector.
void objfun_impl(fitness_vector &, const decision_vector &) const
Implementation of the objective function.
Definition: ackley.cpp:69
void set_ub(const decision_vector &)
Set upper bounds from pagmo::decision_vector.
std::vector< double > fitness_vector
Fitness vector type.
Definition: types.h:42
The Ackley problem.
Definition: ackley.h:51