Stan Math Library  2.20.0
reverse mode automatic differentiation
Phi.hpp
Go to the documentation of this file.
1 #ifndef STAN_MATH_FWD_SCAL_FUN_PHI_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_PHI_HPP
3 
4 #include <stan/math/fwd/meta.hpp>
5 #include <stan/math/fwd/core.hpp>
8 
9 namespace stan {
10 namespace math {
11 
12 template <typename T>
13 inline fvar<T> Phi(const fvar<T>& x) {
14  using std::exp;
15  using std::sqrt;
16  T xv = x.val_;
17  return fvar<T>(Phi(xv), x.d_ * exp(xv * xv / -2.0) / sqrt(2.0 * pi()));
18 }
19 
20 } // namespace math
21 } // namespace stan
22 #endif
T d_
The tangent (derivative) of this variable.
Definition: fvar.hpp:50
fvar< T > sqrt(const fvar< T > &x)
Definition: sqrt.hpp:13
T val_
The value of this variable.
Definition: fvar.hpp:45
fvar< T > exp(const fvar< T > &x)
Definition: exp.hpp:11
fvar< T > Phi(const fvar< T > &x)
Definition: Phi.hpp:13
double pi()
Return the value of pi.
Definition: constants.hpp:80
This template class represents scalars used in forward-mode automatic differentiation, which consist of values and directional derivatives of the specified template type.
Definition: fvar.hpp:41

     [ Stan Home Page ] © 2011–2018, Stan Development Team.