Stan Math Library  2.15.0
reverse mode automatic differentiation
tgamma.hpp
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1 #ifndef STAN_MATH_FWD_SCAL_FUN_TGAMMA_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_TGAMMA_HPP
3 
4 #include <stan/math/fwd/core.hpp>
6 #include <boost/math/special_functions/digamma.hpp>
7 
8 namespace stan {
9  namespace math {
10 
19  template <typename T>
20  inline fvar<T> tgamma(const fvar<T>& x) {
22  T u = tgamma(x.val_);
23  return fvar<T>(u, x.d_ * u * digamma(x.val_));
24  }
25  }
26 }
27 #endif
fvar< T > tgamma(const fvar< T > &x)
Return the result of applying the gamma function to the specified argument.
Definition: tgamma.hpp:20
fvar< T > digamma(const fvar< T > &x)
Return the derivative of the log gamma function at the specified argument.
Definition: digamma.hpp:22

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