All Classes Namespaces Files Functions Variables Typedefs Enumerator Friends Macros Groups
Phi.hpp
Go to the documentation of this file.
#ifndef STAN_MATH_REV_SCAL_FUN_PHI_HPP
#define STAN_MATH_REV_SCAL_FUN_PHI_HPP
#include <stan/math/rev/core.hpp>
#include <stan/math/prim/scal/fun/Phi.hpp>
namespace stan {
namespace math {
namespace {
class Phi_vari : public op_v_vari {
public:
explicit Phi_vari(vari* avi) :
op_v_vari(stan::math::Phi(avi->val_), avi) {
}
void chain() {
static const double NEG_HALF = -0.5;
avi_->adj_ += adj_
* stan::math::INV_SQRT_TWO_PI
* std::exp(NEG_HALF * avi_->val_ * avi_->val_);
}
};
}
inline var Phi(const stan::math::var& a) {
return var(new Phi_vari(a.vi_));
}
}
}
#endif
stan::math::INV_SQRT_TWO_PI
const double INV_SQRT_TWO_PI
Definition: constants.hpp:166
core.hpp
stan::math::var
Independent (input) and dependent (output) variables for gradients.
Definition: var.hpp:32
stan::math::exp
fvar< T > exp(const fvar< T > &x)
Definition: exp.hpp:10
stan::math::var::vi_
vari * vi_
Pointer to the implementation of this variable.
Definition: var.hpp:44
stan::math::Phi
fvar< T > Phi(const fvar< T > &x)
Definition: Phi.hpp:14
Phi.hpp

[ Stan Home Page ] © 2011–2015, Stan Development Team.