Stan Math Library  2.20.0
reverse mode automatic differentiation
lmgamma.hpp
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1 #ifndef STAN_MATH_FWD_SCAL_FUN_LMGAMMA_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_LMGAMMA_HPP
3 
4 #include <stan/math/fwd/meta.hpp>
5 #include <stan/math/fwd/core.hpp>
8 
9 namespace stan {
10 namespace math {
11 
12 template <typename T>
14  int x1, const fvar<T>& x2) {
15  using std::log;
16  T deriv = 0;
17  for (int count = 1; count < x1 + 1; count++)
18  deriv += x2.d_ * digamma(x2.val_ + (1.0 - count) / 2.0);
20  deriv);
21 }
22 } // namespace math
23 } // namespace stan
24 #endif
T d_
The tangent (derivative) of this variable.
Definition: fvar.hpp:50
fvar< T > log(const fvar< T > &x)
Definition: log.hpp:12
T val_
The value of this variable.
Definition: fvar.hpp:45
fvar< typename stan::return_type< T, int >::type > lmgamma(int x1, const fvar< T > &x2)
Definition: lmgamma.hpp:13
This template class represents scalars used in forward-mode automatic differentiation, which consist of values and directional derivatives of the specified template type.
Definition: fvar.hpp:41
fvar< T > digamma(const fvar< T > &x)
Return the derivative of the log gamma function at the specified argument.
Definition: digamma.hpp:23

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