#ifndef STAN_MATH_PRIM_SCAL_FUN_ACOSH_HPP #define STAN_MATH_PRIM_SCAL_FUN_ACOSH_HPP #include #include namespace stan { namespace math { /** * Return the inverse hyperbolic cosine of the specified value. * * @param[in] x Argument. * @return Inverse hyperbolic cosine of the argument. * @throw std::domain_error If argument is less than 1. */ inline double acosh(double x) { return boost::math::acosh(x, boost_policy_t()); } /** * Integer version of acosh. * * @param[in] x Argument. * @return Natural logarithm of one plus the argument. * @throw std::domain_error If argument is less than 1. */ inline double acosh(int x) { return acosh(static_cast(x)); } } } #endif