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#ifndef ROL_STDVECTOR_H
#define ROL_STDVECTOR_H

#include <algorithm>
#include <cstdlib>

#include "ROL_Vector.hpp"

/** \class ROL::StdVector
    \brief Provides the std::vector implementation of the ROL::Vector interface.
*/


namespace ROL {

template <class Real, class Element=Real>
class StdVector : public Vector<Real> {

  typedef typename std::vector<Real>::size_type uint;

private:

  Teuchos::RCP<std::vector<Element> >  std_vec_;

public:

  StdVector(const Teuchos::RCP<std::vector<Element> > & std_vec) : std_vec_(std_vec) {}

  void set( const Vector<Real> &x ) {

    TEUCHOS_TEST_FOR_EXCEPTION( dimension() != x.dimension(),
                                std::invalid_argument,
                                "Error: Vectors must have the same dimension." );

    const StdVector &ex = Teuchos::dyn_cast<const StdVector>(x);
    const std::vector<Element>& xval = *ex.getVector();
    std::copy(xval.begin(),xval.end(),std_vec_->begin());   
  }

  void plus( const Vector<Real> &x ) {

    TEUCHOS_TEST_FOR_EXCEPTION( dimension() != x.dimension(),
                                std::invalid_argument,
                                "Error: Vectors must have the same dimension." );

    const StdVector &ex = Teuchos::dyn_cast<const StdVector>(x);
    const std::vector<Element>& xval = *ex.getVector();
    uint dim  = std_vec_->size();
    for (uint i=0; i<dim; i++) {
      (*std_vec_)[i] += xval[i];
    }
  }

  void axpy( const Real alpha, const Vector<Real> &x ) {

    TEUCHOS_TEST_FOR_EXCEPTION( dimension() != x.dimension(),
                                std::invalid_argument,
                                "Error: Vectors must have the same dimension." );

    const StdVector &ex = Teuchos::dyn_cast<const StdVector>(x);
    const std::vector<Element>& xval = *ex.getVector();
    uint dim  = std_vec_->size();
    for (uint i=0; i<dim; i++) {
      (*std_vec_)[i] += alpha*xval[i];
    }
  }

  void scale( const Real alpha ) {
    uint dim = std_vec_->size();
    for (uint i=0; i<dim; i++) {
      (*std_vec_)[i] *= alpha;
    }
  }

  virtual Real dot( const Vector<Real> &x ) const {

    TEUCHOS_TEST_FOR_EXCEPTION( dimension() != x.dimension(),
                                std::invalid_argument,
                                "Error: Vectors must have the same dimension." );

    const StdVector & ex = Teuchos::dyn_cast<const StdVector>(x);
    const std::vector<Element>& xval = *ex.getVector();
    uint dim  = std_vec_->size();
    Real val = 0;
    for (uint i=0; i<dim; i++) {
      val += (*std_vec_)[i]*xval[i];
    }
    return val;
  }

  Real norm() const {
    Real val = 0;
    val = std::sqrt( dot(*this) );
    return val;
  }

  virtual Teuchos::RCP<Vector<Real> > clone() const {
    return Teuchos::rcp( new StdVector( Teuchos::rcp(new std::vector<Element>(std_vec_->size())) ));
  }

  Teuchos::RCP<const std::vector<Element> > getVector() const {
    return std_vec_;
  }

  Teuchos::RCP<std::vector<Element> > getVector() {
    return std_vec_;
  }

  Teuchos::RCP<Vector<Real> > basis( const int i ) const {

    TEUCHOS_TEST_FOR_EXCEPTION( i >= dimension() || i<0,
                                std::invalid_argument,
                                "Error: Basis index must be between 0 and vector dimension." );

    Teuchos::RCP<StdVector> e = Teuchos::rcp( new StdVector( Teuchos::rcp(new std::vector<Element>(std_vec_->size(), 0.0)) ));
    (*e->getVector())[i] = 1.0;
    return e;
  }

  int dimension() const {
    return static_cast<int>(std_vec_->size());
  }

  void applyUnary( const Elementwise::UnaryFunction<Real> &f ) {
    uint dim  = std_vec_->size();
    for(uint i=0; i<dim; ++i) {
      (*std_vec_)[i] = f.apply((*std_vec_)[i]);
    }
  }

  void applyBinary( const Elementwise::BinaryFunction<Real> &f, const Vector<Real> &x ) {

    TEUCHOS_TEST_FOR_EXCEPTION( dimension() != x.dimension(),
                                std::invalid_argument,
                                "Error: Vectors must have the same dimension." );

    const StdVector & ex = Teuchos::dyn_cast<const StdVector>(x);
    const std::vector<Element>& xval = *ex.getVector();
    uint dim  = std_vec_->size();
    for (uint i=0; i<dim; i++) {
      (*std_vec_)[i] = f.apply((*std_vec_)[i],xval[i]);
    }

  }

  Real reduce( const Elementwise::ReductionOp<Real> &r ) const {
    Real result = r.initialValue();
    uint dim  = std_vec_->size();
    for(uint i=0; i<dim; ++i) {
      r.reduce((*std_vec_)[i],result);
    }
    return result;
  }

  void print( std::ostream &outStream ) const {
    uint dim = std_vec_->size();
    for(uint i=0; i<dim; ++i) {
      outStream << (*std_vec_)[i] << " ";
    }
    outStream << std::endl;
  }

}; // class StdVector




} // namespace ROL

#endif
