Stan Math Library  2.10.0
reverse mode automatic differentiation
atan.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_ATAN_HPP
2 #define STAN_MATH_REV_SCAL_FUN_ATAN_HPP
3 
4 #include <stan/math/rev/core.hpp>
5 #include <cmath>
6 #include <valarray>
7 
8 namespace stan {
9  namespace math {
10 
11  namespace {
12  class atan_vari : public op_v_vari {
13  public:
14  explicit atan_vari(vari* avi) :
15  op_v_vari(std::atan(avi->val_), avi) {
16  }
17  void chain() {
18  avi_->adj_ += adj_ / (1.0 + (avi_->val_ * avi_->val_));
19  }
20  };
21  }
22 
55  inline var atan(const var& a) {
56  return var(new atan_vari(a.vi_));
57  }
58 
59  }
60 }
61 #endif
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:31
fvar< T > atan(const fvar< T > &x)
Definition: atan.hpp:12
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:43

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