Stan Math Library  2.20.0
reverse mode automatic differentiation
atanh.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_ATANH_HPP
2 #define STAN_MATH_REV_SCAL_FUN_ATANH_HPP
3 
4 #include <stan/math/rev/meta.hpp>
6 #include <stan/math/rev/core.hpp>
7 
8 namespace stan {
9 namespace math {
10 
11 namespace internal {
12 class atanh_vari : public op_v_vari {
13  public:
14  atanh_vari(double val, vari* avi) : op_v_vari(val, avi) {}
15  void chain() { avi_->adj_ += adj_ / (1.0 - avi_->val_ * avi_->val_); }
16 };
17 } // namespace internal
18 
58 inline var atanh(const var& a) {
59  return var(new internal::atanh_vari(atanh(a.val()), a.vi_));
60 }
61 
62 } // namespace math
63 } // namespace stan
64 #endif
fvar< T > atanh(const fvar< T > &x)
Return inverse hyperbolic tangent of specified value.
Definition: atanh.hpp:22
The variable implementation base class.
Definition: vari.hpp:30
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:33
friend class var
Definition: vari.hpp:32
const double val_
The value of this variable.
Definition: vari.hpp:38
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:45
atanh_vari(double val, vari *avi)
Definition: atanh.hpp:14
double adj_
The adjoint of this variable, which is the partial derivative of this variable with respect to the ro...
Definition: vari.hpp:44
void chain()
Apply the chain rule to this variable based on the variables on which it depends. ...
Definition: atanh.hpp:15
double val() const
Return the value of this variable.
Definition: var.hpp:294

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