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/*! \file  test_02.cpp
    \brief Test creating a LineSearch using an externally provided 
           scalar minimization function. 
*/
#include "Teuchos_GlobalMPISession.hpp"

#include "Teuchos_GlobalMPISession.hpp"

#include "ROL_Algorithm.hpp"
#include "ROL_BisectionScalarMinimization.hpp"
#include "ROL_LineSearchStep.hpp"
#include "ROL_StatusTest.hpp"
#include "ROL_StdVector.hpp"
#include "ROL_Zakharov.hpp"


typedef double RealT;

int main(int argc, char *argv[] ) {

  Teuchos::GlobalMPISession mpiSession(&argc, &argv);

   
  using namespace ROL;

  typedef std::vector<RealT> vector;
  typedef Vector<RealT>      V;
  typedef StdVector<RealT>   SV;

  // This little trick lets us print to std::cout only if a (dummy) command-line argument is provided.
  int iprint     = argc - 1;
  ROL::Ptr<std::ostream> outStream;
  ROL::nullstream bhs; // outputs nothing
  if (iprint > 0)
    outStream = ROL::makePtrFromRef(std::cout);
  else
    outStream = ROL::makePtrFromRef(bhs);

  // Save the format state of the original std::cout.
  ROL::nullstream oldFormatState;
  oldFormatState.copyfmt(std::cout);

  int errorFlag  = 0;

  // *** Test body.
  try {

    int dim = 10;
   
    ROL::Ptr<vector> x_ptr = ROL::makePtr<vector>( dim, 0.0 );
    ROL::Ptr<vector> k_ptr = ROL::makePtr<vector>( dim, 0.0 );

    for (int i=0; i<dim; i++) {
      (*x_ptr)[i]   = 2;
      (*k_ptr)[i]   = i+1.0;
    }

    ROL::Ptr<V> k = ROL::makePtr<SV>(k_ptr);
    SV x(x_ptr);

    ZOO::Objective_Zakharov<RealT> obj(k);

    ROL::ParameterList parlist;

    parlist.sublist("Scalar Minimization").set("Type","Bisection");
    parlist.sublist("Scalar Minimization").sublist("Bisection").set("Tolerance",1.e-10);
    parlist.sublist("Scalar Minimization").sublist("Bisection").set("Iteration Limit",1000);

    ROL::Ptr<ScalarMinimization<RealT>> sm = ROL::makePtr<BisectionScalarMinimization<RealT>>(parlist);
    ROL::Ptr<LineSearch<RealT>>         ls = ROL::makePtr<ScalarMinimizationLineSearch<RealT>>(parlist, sm);
    ROL::Ptr<Step<RealT>>             step = ROL::makePtr<LineSearchStep<RealT>>( parlist, ls );
    ROL::Ptr<StatusTest<RealT>>     status = ROL::makePtr<StatusTest<RealT>>(parlist);

    Algorithm<RealT> algo( step, status, false );
 
    algo.run(x, obj, true, *outStream);  

    RealT abserr = x.norm();

    *outStream << std::scientific << "\n   Absolute Error: " << abserr << std::endl;
    if ( abserr > sqrt(ROL::ROL_EPSILON<RealT>()) ) {
      errorFlag += 1;
    }

  }
  catch (std::logic_error& err) {
    *outStream << err.what() << "\n";
    errorFlag = -1000;
  }; // end try

  if (errorFlag != 0)
    std::cout << "End Result: TEST FAILED\n";
  else
    std::cout << "End Result: TEST PASSED\n";

  // reset format state of std::cout
  std::cout.copyfmt(oldFormatState);


  return 0;
}


