#include <boost/math/tools/promotion.hpp>

using namespace boost::math;
using namespace std;

template <typename T0__, typename T1__, typename T2__, typename T3__>
typename boost::math::tools::promote_args<T0__, T1__, T2__, T3__>::type
  parabola_function(const T0__& A,
                    const T1__& B,
                    const T2__& C,
                    const T3__& X, std::ostream* pstream__) 
  {
    return A*X*X+B*X+C;
  }