Stan Math Library  2.12.0
reverse mode automatic differentiation
inv_Phi.hpp
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1 #ifndef STAN_MATH_REV_SCAL_FUN_INV_PHI_HPP
2 #define STAN_MATH_REV_SCAL_FUN_INV_PHI_HPP
3 
4 #include <stan/math/rev/core.hpp>
8 
9 namespace stan {
10  namespace math {
11 
12  namespace {
13  class inv_Phi_vari : public op_v_vari {
14  public:
15  explicit inv_Phi_vari(vari* avi) :
16  op_v_vari(inv_Phi(avi->val_), avi) {
17  }
18  void chain() {
19  static const double NEG_HALF = -0.5;
20  avi_->adj_ += adj_
22  / std::exp(NEG_HALF * val_ * val_);
23  }
24  };
25  }
26 
37  inline var inv_Phi(const var& p) {
38  return var(new inv_Phi_vari(p.vi_));
39  }
40 
41  }
42 }
43 #endif
fvar< T > inv_Phi(const fvar< T > &p)
Definition: inv_Phi.hpp:14
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:30
const double SQRT_2_TIMES_SQRT_PI
Definition: constants.hpp:156
fvar< T > exp(const fvar< T > &x)
Definition: exp.hpp:10
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:42

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