Stan Math Library  2.20.0
reverse mode automatic differentiation
round.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_ROUND_HPP
2 #define STAN_MATH_REV_SCAL_FUN_ROUND_HPP
3 
4 #include <stan/math/rev/meta.hpp>
5 #include <stan/math/rev/core.hpp>
8 #include <limits>
9 
10 namespace stan {
11 namespace math {
12 
13 namespace internal {
14 class round_vari : public op_v_vari {
15  public:
16  explicit round_vari(vari* avi) : op_v_vari(round(avi->val_), avi) {}
17  void chain() {
18  if (unlikely(is_nan(avi_->val_)))
19  avi_->adj_ = std::numeric_limits<double>::quiet_NaN();
20  }
21 };
22 } // namespace internal
23 
54 inline var round(const var& a) { return var(new internal::round_vari(a.vi_)); }
55 
56 } // namespace math
57 } // namespace stan
58 #endif
The variable implementation base class.
Definition: vari.hpp:30
fvar< T > round(const fvar< T > &x)
Return the closest integer to the specified argument, with halfway cases rounded away from zero...
Definition: round.hpp:24
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
#define unlikely(x)
Definition: likely.hpp:9
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:45
double adj_
The adjoint of this variable, which is the partial derivative of this variable with respect to the ro...
Definition: vari.hpp:44
int is_nan(const fvar< T > &x)
Returns 1 if the input&#39;s value is NaN and 0 otherwise.
Definition: is_nan.hpp:20
void chain()
Apply the chain rule to this variable based on the variables on which it depends. ...
Definition: round.hpp:17

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