mdivide_right.hpp

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#ifndef STAN__MATH__MATRIX__MDIVIDE_RIGHT_HPP
#define STAN__MATH__MATRIX__MDIVIDE_RIGHT_HPP

#include <boost/math/tools/promotion.hpp>
#include <stan/math/matrix/Eigen.hpp>
#include <stan/math/matrix/mdivide_left.hpp>
#include <stan/math/matrix/transpose.hpp>
#include <stan/math/error_handling/matrix/check_multiplicable.hpp>
#include <stan/math/error_handling/matrix/check_square.hpp>

namespace stan {
  namespace math {

    template <typename T1, typename T2, int R1, int C1, int R2, int C2>
    inline 
    Eigen::Matrix<typename boost::math::tools::promote_args<T1,T2>::type,R1,C2>
    mdivide_right(const Eigen::Matrix<T1,R1,C1> &b,
                  const Eigen::Matrix<T2,R2,C2> &A) {
      stan::math::check_square("mdivide_right(%1%)",A,"A",(double*)0);
      stan::math::check_multiplicable("mdivide_right(%1%)",b,"b",
                                      A,"A",(double*)0);
      // FIXME: This is nice and general but likely slow.
      return transpose(mdivide_left(transpose(A),transpose(b)));
//      return promote_common<Eigen::Matrix<T1,R2,C2>,
//                            Eigen::Matrix<T2,R2,C2> >(A)
//        .transpose()
//        .lu()
//        .solve(promote_common<Eigen::Matrix<T1,R1,C1>,
//                              Eigen::Matrix<T2,R1,C1> >(b)
//               .transpose())
//        .transpose();
    }

  }
}
#endif