1 #ifndef STAN_MATH_REV_SCAL_FUN_PHI_APPROX_HPP
2 #define STAN_MATH_REV_SCAL_FUN_PHI_APPROX_HPP
51 double av_squared = av * av;
52 double av_cubed = av * av_squared;
54 double da = f * (1 - f) * (3.0 * 0.07056 * av_squared + 1.5976);
fvar< T > inv_logit(const fvar< T > &x)
Independent (input) and dependent (output) variables for gradients.
boost::math::tools::promote_args< T >::type Phi_approx(T x)
Approximation of the unit normal CDF.
const double val_
The value of this variable.
vari * vi_
Pointer to the implementation of this variable.