#ifndef STAN_MATH_FWD_MAT_FUN_QUAD_FORM_SYM_HPP
#define STAN_MATH_FWD_MAT_FUN_QUAD_FORM_SYM_HPP

#include <stan/math/fwd/core.hpp>
#include <stan/math/fwd/mat/fun/multiply.hpp>
#include <stan/math/fwd/mat/fun/dot_product.hpp>

namespace stan {
namespace math {

template <int RA, int CA, int RB, int CB, typename T>
inline Eigen::Matrix<fvar<T>, CB, CB> quad_form_sym(
    const Eigen::Matrix<fvar<T>, RA, CA>& A,
    const Eigen::Matrix<double, RB, CB>& B) {
  check_square("quad_form_sym", "A", A);
  check_multiplicable("quad_form_sym", "A", A, "B", B);
  check_symmetric("quad_form_sym", "A", A);
  Eigen::Matrix<fvar<T>, CB, CB> ret(multiply(transpose(B), multiply(A, B)));
  return T(0.5) * (ret + transpose(ret));
}

template <int RA, int CA, int RB, typename T>
inline fvar<T> quad_form_sym(const Eigen::Matrix<fvar<T>, RA, CA>& A,
                             const Eigen::Matrix<double, RB, 1>& B) {
  check_square("quad_form_sym", "A", A);
  check_multiplicable("quad_form_sym", "A", A, "B", B);
  check_symmetric("quad_form_sym", "A", A);
  return dot_product(B, multiply(A, B));
}
template <int RA, int CA, int RB, int CB, typename T>
inline Eigen::Matrix<fvar<T>, CB, CB> quad_form_sym(
    const Eigen::Matrix<double, RA, CA>& A,
    const Eigen::Matrix<fvar<T>, RB, CB>& B) {
  check_square("quad_form_sym", "A", A);
  check_multiplicable("quad_form_sym", "A", A, "B", B);
  check_symmetric("quad_form_sym", "A", A);
  Eigen::Matrix<fvar<T>, CB, CB> ret(multiply(transpose(B), multiply(A, B)));
  return T(0.5) * (ret + transpose(ret));
}

template <int RA, int CA, int RB, typename T>
inline fvar<T> quad_form_sym(const Eigen::Matrix<double, RA, CA>& A,
                             const Eigen::Matrix<fvar<T>, RB, 1>& B) {
  check_square("quad_form_sym", "A", A);
  check_multiplicable("quad_form_sym", "A", A, "B", B);
  check_symmetric("quad_form_sym", "A", A);
  return dot_product(B, multiply(A, B));
}
}  // namespace math
}  // namespace stan

#endif
