1 #ifndef STAN_MATH_FWD_SCAL_FUN_INV_LOGIT_HPP 2 #define STAN_MATH_FWD_SCAL_FUN_INV_LOGIT_HPP 3 4 #include <stan/math/fwd/core.hpp> 5 6 #include <stan/math/prim/scal/fun/inv_logit.hpp> 7 8 namespace stan { 9 namespace math { 10 11 /** 12 * Returns the inverse logit function applied to the argument. 13 * 14 * @tparam T scalar type of forward-mode autodiff variable 15 * argument. 16 * @param x argument 17 * @return inverse logit of argument 18 */ 19 template <typename T> inv_logit(const fvar<T> & x)20inline fvar<T> inv_logit(const fvar<T>& x) { 21 using std::exp; 22 using std::pow; 23 return fvar<T>(inv_logit(x.val_), 24 x.d_ * inv_logit(x.val_) * (1 - inv_logit(x.val_))); 25 } 26 } // namespace math 27 } // namespace stan 28 #endif 29