ROL
rosenbrock/example_01.cpp
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43 
49 #define USE_HESSVEC 1
50 
51 #include "ROL_Rosenbrock.hpp"
52 #include "ROL_Algorithm.hpp"
53 #include "ROL_LineSearchStep.hpp"
54 #include "ROL_StatusTest.hpp"
55 #include "ROL_Stream.hpp"
56 #include "Teuchos_GlobalMPISession.hpp"
57 
58 #include <iostream>
59 
60 typedef double RealT;
61 
62 int main(int argc, char *argv[]) {
63 
64  Teuchos::GlobalMPISession mpiSession(&argc, &argv);
65 
66  // This little trick lets us print to std::cout only if a (dummy) command-line argument is provided.
67  int iprint = argc - 1;
68  ROL::Ptr<std::ostream> outStream;
69  ROL::nullstream bhs; // outputs nothing
70  if (iprint > 0)
71  outStream = ROL::makePtrFromRef(std::cout);
72  else
73  outStream = ROL::makePtrFromRef(bhs);
74 
75  int errorFlag = 0;
76 
77  // *** Example body.
78 
79  try {
80 
82  int dim = 100; // Set problem dimension. Must be even.
83 
84  // Set parameters.
85  ROL::ParameterList parlist;
86  parlist.sublist("Step").sublist("Line Search").sublist("Descent Method").set("Type", "Newton-Krylov");
87  parlist.sublist("Status Test").set("Gradient Tolerance",1.e-12);
88  parlist.sublist("Status Test").set("Step Tolerance",1.e-14);
89  parlist.sublist("Status Test").set("Iteration Limit",100);
90 
91  // Define algorithm.
92  ROL::Ptr<ROL::Step<RealT>>
93  step = ROL::makePtr<ROL::LineSearchStep<RealT>>(parlist);
94  ROL::Ptr<ROL::StatusTest<RealT>>
95  status = ROL::makePtr<ROL::StatusTest<RealT>>(parlist);
96  ROL::Algorithm<RealT> algo(step,status,false);
97 
98  // Iteration Vector
99  ROL::Ptr<std::vector<RealT> > x_ptr = ROL::makePtr<std::vector<RealT>>(dim, 0.0);
100  // Set Initial Guess
101  for (int i=0; i<dim/2; i++) {
102  (*x_ptr)[2*i] = -1.2;
103  (*x_ptr)[2*i+1] = 1.0;
104  }
105  ROL::StdVector<RealT> x(x_ptr);
106 
107  // Run Algorithm
108  algo.run(x, obj, true, *outStream);
109 
110  // Get True Solution
111  ROL::Ptr<std::vector<RealT> > xtrue_ptr = ROL::makePtr<std::vector<RealT>>(dim, 1.0);
112  ROL::StdVector<RealT> xtrue(xtrue_ptr);
113 
114  // Compute Error
115  x.axpy(-1.0, xtrue);
116  RealT abserr = x.norm();
117  RealT relerr = abserr/xtrue.norm();
118  *outStream << std::scientific << "\n Absolute Error: " << abserr;
119  *outStream << std::scientific << "\n Relative Error: " << relerr << "\n";
120  if ( relerr > sqrt(ROL::ROL_EPSILON<RealT>()) ) {
121  errorFlag += 1;
122  }
123  }
124  catch (std::logic_error& err) {
125  *outStream << err.what() << "\n";
126  errorFlag = -1000;
127  }; // end try
128 
129  if (errorFlag != 0)
130  std::cout << "End Result: TEST FAILED\n";
131  else
132  std::cout << "End Result: TEST PASSED\n";
133 
134  return 0;
135 
136 }
137 
void axpy(const Real alpha, const Vector< Real > &x)
Compute where .
Rosenbrock&#39;s function.
Contains definitions for Rosenbrock&#39;s function.
Defines a no-output stream class ROL::NullStream and a function makeStreamPtr which either wraps a re...
Real norm() const
Returns where .
Provides the ROL::Vector interface for scalar values, to be used, for example, with scalar constraint...
Provides an interface to run optimization algorithms.
basic_nullstream< char, char_traits< char >> nullstream
Definition: ROL_Stream.hpp:72
int main(int argc, char *argv[])
constexpr auto dim