1 #ifndef STAN_MATH_PRIM_FUN_DOT_PRODUCT_HPP
2 #define STAN_MATH_PRIM_FUN_DOT_PRODUCT_HPP
3
4 #include <stan/math/prim/meta.hpp>
5 #include <stan/math/prim/err.hpp>
6 #include <stan/math/prim/fun/Eigen.hpp>
7 #include <vector>
8
9 namespace stan {
10 namespace math {
11
12 /**
13 * Returns the dot product of the specified vectors.
14 *
15 * @param v1 First vector.
16 * @param v2 Second vector.
17 * @return Dot product of the vectors.
18 * @throw std::invalid_argument If the vectors are not the same
19 * size or if they are both not vector dimensioned.
20 */
21 template <typename Vec1, typename Vec2,
22 require_all_eigen_vector_t<Vec1, Vec2> * = nullptr,
23 require_not_var_t<return_type_t<Vec1, Vec2>> * = nullptr>
dot_product(const Vec1 & v1,const Vec2 & v2)24 inline auto dot_product(const Vec1 &v1, const Vec2 &v2) {
25 check_matching_sizes("dot_product", "v1", v1, "v2", v2);
26 return v1.dot(v2);
27 }
28
29 /**
30 * Returns the dot product of the specified arrays.
31 *
32 * @param v1 First array.
33 * @param v2 Second array.
34 * @param length Length of both arrays.
35 */
36 template <typename Scalar1, typename Scalar2,
37 require_all_stan_scalar_t<Scalar1, Scalar2> * = nullptr,
38 require_all_not_var_t<Scalar1, Scalar2> * = nullptr>
dot_product(const Scalar1 * v1,const Scalar2 * v2,size_t length)39 inline auto dot_product(const Scalar1 *v1, const Scalar2 *v2, size_t length) {
40 return_type_t<Scalar1, Scalar2> result = 0;
41 for (size_t i = 0; i < length; i++) {
42 result += v1[i] * v2[i];
43 }
44 return result;
45 }
46
47 /**
48 * Returns the dot product of the specified arrays.
49 *
50 * @param v1 First array.
51 * @param v2 Second array.
52 * @throw std::domain_error if the vectors are not the same size.
53 */
54 template <typename Scalar1, typename Scalar2, typename Alloc1, typename Alloc2,
55 require_all_stan_scalar_t<Scalar1, Scalar2> * = nullptr>
dot_product(const std::vector<Scalar1,Alloc1> & v1,const std::vector<Scalar2,Alloc2> & v2)56 inline return_type_t<Scalar1, Scalar2> dot_product(
57 const std::vector<Scalar1, Alloc1> &v1,
58 const std::vector<Scalar2, Alloc2> &v2) {
59 check_matching_sizes("dot_product", "v1", v1, "v2", v2);
60
61 if (v1.size() == 0) {
62 return 0.0;
63 }
64
65 return dot_product(as_column_vector_or_scalar(v1),
66 as_column_vector_or_scalar(v2));
67 }
68
69 } // namespace math
70 } // namespace stan
71
72 #endif
73