1 #ifndef STAN_MATH_PRIM_SCAL_FUN_LOG_FALLING_FACTORIAL_HPP 2 #define STAN_MATH_PRIM_SCAL_FUN_LOG_FALLING_FACTORIAL_HPP 53 template<
typename T1,
typename T2>
54 inline typename boost::math::tools::promote_args<T1, T2>::type
57 return std::numeric_limits<double>::quiet_NaN();
58 static const char* fun =
"log_falling_factorial";
fvar< T > log_falling_factorial(const fvar< T > &x, const fvar< T > &n)
fvar< T > lgamma(const fvar< T > &x)
Return the natural logarithm of the gamma function applied to the specified argument.
void check_positive(const char *function, const char *name, const T_y &y)
Check if y is positive.
int is_nan(const fvar< T > &x)
Returns 1 if the input's value is NaN and 0 otherwise.