log1m_exp() [4/6]

double stan::math::log1m_exp ( double  a )

inline

Calculates the natural logarithm of one minus the exponential of the specified value without overflow,.

log1m_exp(x) = log(1-exp(x))

This function is only defined for x < 0

\[ \mbox{log1m\_exp}(x) = \begin{cases} \ln(1-\exp(x)) & \mbox{if } x < 0 \\ \textrm{NaN} & \mbox{if } x \geq 0\\[6pt] \textrm{NaN} & \mbox{if } x = \textrm{NaN} \end{cases} \]

\[ \frac{\partial\, \mbox{asinh}(x)}{\partial x} = \begin{cases} -\frac{\exp(x)}{1-\exp(x)} & \mbox{if } x < 0 \\ \textrm{NaN} & \mbox{if } x \geq 0\\[6pt] \textrm{NaN} & \mbox{if } x = \textrm{NaN} \end{cases} \]

Parameters

[in]

a

Argument.

Returns

natural logarithm of one minus the exponential of the argument.

Definition at line 47 of file log1m_exp.hpp.