Stan Math Library  2.8.0
reverse mode automatic differentiation
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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 
4 #include <boost/math/special_functions/digamma.hpp>
5 #include <stan/math/rev/core.hpp>
6 
7 namespace stan {
8  namespace math {
9 
10  namespace {
11  class tgamma_vari : public op_v_vari {
12  public:
13  explicit tgamma_vari(vari* avi) :
14  op_v_vari(boost::math::tgamma(avi->val_), avi) {
15  }
16  void chain() {
17  avi_->adj_ += adj_ * val_ * boost::math::digamma(avi_->val_);
18  }
19  };
20  }
21 
65  inline var tgamma(const stan::math::var& a) {
66  return var(new tgamma_vari(a.vi_));
67  }
68 
69  }
70 }
71 #endif
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:32
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:44
fvar< T > tgamma(const fvar< T > &x)
Definition: tgamma.hpp:15
fvar< T > digamma(const fvar< T > &x)
Definition: digamma.hpp:16

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