1 #ifndef STAN_MATH_PRIM_SCAL_FUN_ISNAN_HPP 2 #define STAN_MATH_PRIM_SCAL_FUN_ISNAN_HPP 3 4 #include <stan/math/prim/meta.hpp> 5 #include <stan/math/prim/fun/is_nan.hpp> 6 7 namespace stan { 8 namespace math { 9 10 /** 11 * Return true if specified argument is not-a-number. 12 * 13 * Overloads `std::isnan` from `<cmath>` for argument-dependent 14 * lookup. 15 * 16 * @tparam ADType type of argument 17 * @param[in] x argument 18 * @return true if argument is not-a-number 19 */ 20 template <typename T, typename = require_autodiff_t<T>> isnan(const T & x)21inline bool isnan(const T& x) { 22 return is_nan(x); 23 } 24 25 } // namespace math 26 } // namespace stan 27 28 #endif 29