ROL
ROL_Minimax1.hpp
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43 
44 #ifndef ROL_MINIMAX1_HPP
45 #define ROL_MINIMAX1_HPP
46 
47 #include "ROL_Objective.hpp"
48 #include "ROL_Vector.hpp"
49 #include "ROL_StdVector.hpp"
50 
51 #include "Teuchos_RCP.hpp"
52 
53 namespace ROL {
54 
55 template<class Real>
56 class Minimax1 : public Objective<Real> {
57 public:
58  Minimax1(void) {}
59 
60  Real value(const Vector<Real> &x, Real &tol) {
61  Teuchos::RCP<const std::vector<Real> > xp =
62  (Teuchos::dyn_cast<StdVector<Real> >(const_cast<Vector<Real> &>(x))).getVector();
63  Real f1 = std::pow((*xp)[0],2.0) + std::pow((*xp)[1],4.0);
64  Real f2 = std::pow(2.0-(*xp)[0],2.0) + std::pow(2.0-(*xp)[1],2.0);
65  Real f3 = 2.0*std::exp(-(*xp)[0] + (*xp)[1]);
66  return std::max(f1,std::max(f2,f3));
67  }
68 
69  void gradient(Vector<Real> &g, const Vector<Real> &x, Real &tol) {
70  Teuchos::RCP<const std::vector<Real> > xp =
71  (Teuchos::dyn_cast<StdVector<Real> >(const_cast<Vector<Real> &>(x))).getVector();
72  Teuchos::RCP<std::vector<Real> > gp =
73  Teuchos::rcp_const_cast<std::vector<Real> >((Teuchos::dyn_cast<StdVector<Real> >(g)).getVector());
74  Real f1 = std::pow((*xp)[0],2.0) + std::pow((*xp)[1],4.0);
75  Real f2 = std::pow(2.0-(*xp)[0],2.0) + std::pow(2.0-(*xp)[1],2.0);
76  Real f3 = 2.0*std::exp(-(*xp)[0] + (*xp)[1]);
77 
78  //int ind = ((f1 >= f2) ? ((f1 < f3) ? 3 : 1) : ((f2 < f3) ? 3 : 2));
79  if( f1 >= std::max(f2,f3) ) {
80  (*gp)[0] = 2.0*(*xp)[0];
81  (*gp)[1] = 4.0*std::pow((*xp)[1],3.0);
82  }
83  else if ( f2 >= std::max(f1,f3) ) {
84  (*gp)[0] = 2.0*(*xp)[0]-4.0;
85  (*gp)[1] = 2.0*(*xp)[1]-4.0;
86  }
87  else if ( f3 >= std::max(f1,f2) ) {
88  (*gp)[0] = -2.0*std::exp(-(*xp)[0]+(*xp)[1]);
89  (*gp)[1] = 2.0*std::exp(-(*xp)[0]+(*xp)[1]);
90  }
91  }
92 }; // class Minimax1
93 
94 } // namespace ROL
95 
96 #endif
Provides the interface to evaluate objective functions.
Real value(const Vector< Real > &x, Real &tol)
Compute value.
Defines the linear algebra or vector space interface.
Definition: ROL_Vector.hpp:72
void gradient(Vector< Real > &g, const Vector< Real > &x, Real &tol)
Compute gradient.
Provides the std::vector implementation of the ROL::Vector interface.