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erfc.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_ERFC_HPP
2 #define STAN_MATH_REV_SCAL_FUN_ERFC_HPP
3 
4 #include <math.h>
5 #include <stan/math/rev/core.hpp>
7 #include <cmath>
8 #include <valarray>
9 
10 namespace stan {
11  namespace math {
12 
13  namespace {
14  class erfc_vari : public op_v_vari {
15  public:
16  explicit erfc_vari(vari* avi) :
17  op_v_vari(::erfc(avi->val_), avi) {
18  }
19  void chain() {
20  avi_->adj_ += adj_ * stan::math::NEG_TWO_OVER_SQRT_PI
21  * std::exp(- avi_->val_ * avi_->val_);
22  }
23  };
24  }
25 
63  inline var erfc(const var& a) {
64  return var(new erfc_vari(a.vi_));
65  }
66 
67  }
68 }
69 #endif
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:32
fvar< T > exp(const fvar< T > &x)
Definition: exp.hpp:10
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:44
const double NEG_TWO_OVER_SQRT_PI
Definition: constants.hpp:163
fvar< T > erfc(const fvar< T > &x)
Definition: erfc.hpp:14

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