1 #ifndef STAN_MATH_PRIM_FUN_ONES_ROW_VECTOR_HPP
2 #define STAN_MATH_PRIM_FUN_ONES_ROW_VECTOR_HPP
3 
4 #include <stan/math/prim/err.hpp>
5 #include <stan/math/prim/fun/Eigen.hpp>
6 
7 namespace stan {
8 namespace math {
9 
10 /**
11  * Return a row vector of ones
12  *
13  * @param K size of the row vector
14  * @return A row vector of size K with all elements initialised to 1.
15  * @throw std::domain_error if K is negative.
16  */
ones_row_vector(int K)17 inline auto ones_row_vector(int K) {
18   check_nonnegative("ones_row_vector", "size", K);
19   return Eigen::RowVectorXd::Constant(K, 1);
20 }
21 
22 }  // namespace math
23 }  // namespace stan
24 
25 #endif
26