Stan Math Library  2.15.0
reverse mode automatic differentiation
tgamma.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_TGAMMA_HPP
2 #define STAN_MATH_REV_SCAL_FUN_TGAMMA_HPP
3 
6 #include <stan/math/rev/core.hpp>
7 
8 namespace stan {
9  namespace math {
10 
11  namespace {
12  class tgamma_vari : public op_v_vari {
13  public:
14  explicit tgamma_vari(vari* avi) :
15  op_v_vari(tgamma(avi->val_), avi) {
16  }
17  void chain() {
18  avi_->adj_ += adj_ * val_ * digamma(avi_->val_);
19  }
20  };
21  }
22 
61  inline var tgamma(const var& a) {
62  return var(new tgamma_vari(a.vi_));
63  }
64 
65  }
66 }
67 #endif
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:30
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:42
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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