log_inv_logit() [4/7]

double stan::math::log_inv_logit ( double  u )

inline

Returns the natural logarithm of the inverse logit of the specified argument.

$$\mbox{log\_inv\_logit}(x) = \begin{cases} \ln\left(\frac{1}{1+\exp(-x)}\right)& \mbox{if } -\infty\leq x \leq \infty \\[6pt] \textrm{NaN} & \mbox{if } x = \textrm{NaN} \end{cases}$$

$$\frac{\partial\, \mbox{log\_inv\_logit}(x)}{\partial x} = \begin{cases} \frac{1}{1+\exp(x)} & \mbox{if } -\infty\leq x\leq \infty \\[6pt] \textrm{NaN} & \mbox{if } x = \textrm{NaN} \end{cases}$$

Parameters

u

argument

Returns

log of the inverse logit of argument

Definition at line 34 of file log_inv_logit.hpp.