1 #ifndef STAN_MATH_PRIM_FUN_REVERSE_HPP
2 #define STAN_MATH_PRIM_FUN_REVERSE_HPP
3 
4 #include <stan/math/prim/meta.hpp>
5 #include <stan/math/prim/fun/Eigen.hpp>
6 #include <algorithm>
7 #include <vector>
8 
9 namespace stan {
10 namespace math {
11 
12 /**
13  * Return a copy of the specified array in reversed order.
14  *
15  * @tparam T type of elements in the array
16  * @param x array to reverse
17  * @return Array in reversed order.
18  */
19 template <typename T>
reverse(const std::vector<T> & x)20 inline std::vector<T> reverse(const std::vector<T>& x) {
21   std::vector<T> rev(x.size());
22   std::reverse_copy(x.begin(), x.end(), rev.begin());
23   return rev;
24 }
25 
26 /**
27  * Return a copy of the specified vector or row vector
28  * in reversed order.
29  *
30  * @tparam T type of container (vector or row vector)
31  * @param x vector or row vector to reverse
32  * @return Vector or row vector in reversed order.
33  */
34 template <typename T, typename = require_vector_t<T>>
reverse(const T & x)35 inline auto reverse(const T& x) {
36   return x.reverse();
37 }
38 
39 }  // namespace math
40 }  // namespace stan
41 #endif
42