Stan Math Library  2.12.0
reverse mode automatic differentiation
erf.hpp
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1 #ifndef STAN_MATH_FWD_SCAL_FUN_ERF_HPP
2 #define STAN_MATH_FWD_SCAL_FUN_ERF_HPP
3 
4 #include <math.h>
5 #include <stan/math/fwd/core.hpp>
8 #include <cmath>
9 
10 namespace stan {
11  namespace math {
12 
13  template <typename T>
14  inline fvar<T> erf(const fvar<T>& x) {
16  using std::sqrt;
17  using std::exp;
18  return fvar<T>(erf(x.val_),
19  x.d_ * exp(-square(x.val_)) * TWO_OVER_SQRT_PI);
20  }
21 
22  }
23 }
24 #endif
var erf(const var &a)
The error function for variables (C99).
Definition: erf.hpp:68
fvar< T > sqrt(const fvar< T > &x)
Definition: sqrt.hpp:14
fvar< T > erf(const fvar< T > &x)
Definition: erf.hpp:14
fvar< T > square(const fvar< T > &x)
Definition: square.hpp:14
const double TWO_OVER_SQRT_PI
Definition: constants.hpp:159
fvar< T > exp(const fvar< T > &x)
Definition: exp.hpp:10

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