#ifndef STAN_MATH_PRIM_MAT_FUN_COLUMNS_DOT_SELF_HPP
#define STAN_MATH_PRIM_MAT_FUN_COLUMNS_DOT_SELF_HPP

#include <stan/math/prim/mat/fun/Eigen.hpp>

namespace stan {
  namespace math {

    /**
     * Returns the dot product of each column of a matrix with itself.
     * @param x Matrix.
     * @tparam T scalar type
     */
    template<typename T, int R, int C>
    inline Eigen::Matrix<T, 1, C>
    columns_dot_self(const Eigen::Matrix<T, R, C>& x) {
      return x.colwise().squaredNorm();
    }

  }
}
#endif
