Stan Math Library  2.14.0
reverse mode automatic differentiation
Phi_approx.hpp
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1 #ifndef STAN_MATH_PRIM_SCAL_FUN_PHI_APPROX_HPP
2 #define STAN_MATH_PRIM_SCAL_FUN_PHI_APPROX_HPP
3 
5 #include <cmath>
6 
7 namespace stan {
8  namespace math {
9 
21  inline double Phi_approx(double x) {
22  using std::pow;
23  return inv_logit(0.07056 * pow(x, 3.0) + 1.5976 * x);
24  }
25 
33  inline double Phi_approx(int x) {
34  return Phi_approx(static_cast<double>(x));
35  }
36 
37  }
38 }
39 
40 #endif
fvar< T > inv_logit(const fvar< T > &x)
Returns the inverse logit function applied to the argument.
Definition: inv_logit.hpp:20
fvar< T > Phi_approx(const fvar< T > &x)
Return an approximation of the unit normal cumulative distribution function (CDF).
Definition: Phi_approx.hpp:22
fvar< T > pow(const fvar< T > &x1, const fvar< T > &x2)
Definition: pow.hpp:17

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