dot_product.hpp

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#ifndef STAN__MATH__MATRIX__DOT_PRODUCT_HPP
#define STAN__MATH__MATRIX__DOT_PRODUCT_HPP

#include <vector>
#include <stan/math/matrix/Eigen.hpp>
#include <stan/math/error_handling/matrix/check_vector.hpp>
#include <stan/math/error_handling/matrix/check_matching_sizes.hpp>

namespace stan {
  namespace math {
    
    template<int R1,int C1,int R2, int C2>
    inline double dot_product(const Eigen::Matrix<double, R1, C1>& v1, 
                              const Eigen::Matrix<double, R2, C2>& v2) {
      stan::math::check_vector("dot_product(%1%)",v1,"v1",(double*)0);
      stan::math::check_vector("dot_product(%1%)",v2,"v2",(double*)0);
      stan::math::check_matching_sizes("dot_product(%1%)",v1,"v1",
                                       v2,"v2",(double*)0);
      return v1.dot(v2);
    }
    inline double dot_product(const double* v1, const double* v2, 
                              size_t length) {
      double result = 0;
      for (size_t i = 0; i < length; i++)
        result += v1[i] * v2[i];
      return result;
    }
    inline double dot_product(const std::vector<double>& v1,
                              const std::vector<double>& v2) {
      stan::math::check_matching_sizes("dot_product(%1%)",v1,"v1",
                                       v2,"v2",(double*)0);
      return dot_product(&v1[0], &v2[0], v1.size());
    }
    
  }
}
#endif