example_01a.cpp

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// @HEADER
// *****************************************************************************
//               Rapid Optimization Library (ROL) Package
//
// Copyright 2014 NTESS and the ROL contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#include <iostream>

#include "ROL_Sacado_Objective.hpp"

#include "ROL_Algorithm.hpp"
#include "ROL_LineSearchStep.hpp"
#include "ROL_StatusTest.hpp"
#include "ROL_ParameterList.hpp"

#include "ROL_Stream.hpp"
#include "Teuchos_GlobalMPISession.hpp"

#include "example_01a.hpp"

using namespace ROL;

typedef double RealT;

int main(int argc, char **argv)
{
    Teuchos::GlobalMPISession mpiSession(&argc, &argv);

    // 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);

    int errorFlag  = 0;

    // *** Example body.

    try {

        Sacado_Objective<RealT,Zakharov> obj;
    
        int dim = 10; // Set problem dimension. 

        // Load optimizer parameters form XML file
        std::string paramfile = "parameters.xml";
        auto parlist = ROL::getParametersFromXmlFile(paramfile);

        // Define algorithm.
        ROL::Ptr<ROL::Step<RealT>>
          step = ROL::makePtr<ROL::LineSearchStep<RealT>>(*parlist);
        ROL::Ptr<ROL::StatusTest<RealT>>
          status = ROL::makePtr<ROL::StatusTest<RealT>>(*parlist);
        ROL::Algorithm<RealT> algo(step,status,false);

        // Iteration vector.
        ROL::Ptr<std::vector<RealT> > x_ptr = ROL::makePtr<std::vector<RealT>>(dim, 0.0);
        // Set Initial Guess
        for (int i=0; i<dim; i++) {
            (*x_ptr)[i]   = 2;
        }

        StdVector<RealT> x(x_ptr);

        // Run algorithm.
        algo.run(x, obj, true, *outStream);

        // Get true solution.
        ROL::Ptr<std::vector<RealT> > xtrue_ptr = ROL::makePtr<std::vector<RealT>>(dim, 0.0);
        StdVector<RealT> xtrue(xtrue_ptr);
        
        // Compute error.
        x.axpy(-1.0, xtrue);
        RealT abserr = x.norm();
        *outStream << std::scientific << "\n   Absolute Error: " << abserr << std::endl;
        if ( abserr > sqrt(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";

    return 0;

}