ROL
example_01b.cpp
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1 // @HEADER
2 // *****************************************************************************
3 // Rapid Optimization Library (ROL) Package
4 //
5 // Copyright 2014 NTESS and the ROL contributors.
6 // SPDX-License-Identifier: BSD-3-Clause
7 // *****************************************************************************
8 // @HEADER
9 
18 #include <iostream>
19 
20 #include "ROL_Algorithm.hpp"
21 #include "ROL_LineSearchStep.hpp"
22 #include "ROL_StatusTest.hpp"
23 #include "ROL_ParameterList.hpp"
24 
25 #include "ROL_Stream.hpp"
26 #include "Teuchos_GlobalMPISession.hpp"
27 
28 #include "example_01b.hpp"
29 
30 using namespace ROL;
31 
32 typedef double RealT;
33 
34 int main(int argc, char **argv)
35 {
36  Teuchos::GlobalMPISession mpiSession(&argc, &argv);
37 
38  // This little trick lets us print to std::cout only if a (dummy) command-line argument is provided.
39  int iprint = argc - 1;
40  ROL::Ptr<std::ostream> outStream;
41  ROL::nullstream bhs; // outputs nothing
42  if (iprint > 0)
43  outStream = ROL::makePtrFromRef(std::cout);
44  else
45  outStream = ROL::makePtrFromRef(bhs);
46 
47  int errorFlag = 0;
48 
49  // *** Example body.
50 
51  try {
52 
54 
55  int dim = 10; // Set problem dimension.
56 
57  // Load optimizer parameters form XML file
58  std::string paramfile = "parameters.xml";
59  auto parlist = ROL::getParametersFromXmlFile(paramfile);
60 
61  // Define algorithm.
62  ROL::Ptr<ROL::Step<RealT>>
63  step = ROL::makePtr<ROL::LineSearchStep<RealT>>(*parlist);
64  ROL::Ptr<ROL::StatusTest<RealT>>
65  status = ROL::makePtr<ROL::StatusTest<RealT>>(*parlist);
66  ROL::Algorithm<RealT> algo(step,status,false);
67 
68  // Iteration Vector
69  ROL::Ptr<std::vector<RealT> > x_ptr = ROL::makePtr<std::vector<RealT>>(dim, 0.0);
70  // Set Initial Guess
71  for (int i=0; i<dim; i++) {
72  (*x_ptr)[i] = 2;
73  }
74 
75  StdVector<RealT> x(x_ptr);
76 
77  // Run Algorithm
78  algo.run(x, obj, true, *outStream);
79 
80  // Get True Solution
81  ROL::Ptr<std::vector<RealT> > xtrue_ptr = ROL::makePtr<std::vector<RealT>>(dim, 0.0);
82  StdVector<RealT> xtrue(xtrue_ptr);
83 
84 
85  // Compute Error
86  x.axpy(-1.0, xtrue);
87  RealT abserr = x.norm();
88  *outStream << std::scientific << "\n Absolute Error: " << abserr;
89  if ( abserr > sqrt(ROL_EPSILON<RealT>()) ) {
90  errorFlag += 1;
91  }
92  }
93  catch (std::logic_error& err) {
94  *outStream << err.what() << "\n";
95  errorFlag = -1000;
96  }; // end try
97 
98  if (errorFlag != 0)
99  std::cout << "End Result: TEST FAILED\n";
100  else
101  std::cout << "End Result: TEST PASSED\n";
102 
103  return 0;
104 
105 }
void axpy(const Real alpha, const Vector< Real > &x)
Compute where .
virtual std::vector< std::string > run(Vector< Real > &x, Objective< Real > &obj, bool print=false, std::ostream &outStream=std::cout, bool printVectors=false, std::ostream &vectorStream=std::cout)
Run algorithm on unconstrained problems (Type-U). This is the primary Type-U interface.
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:38
int main(int argc, char *argv[])
constexpr auto dim