expit {rje} | R Documentation |
Expit and Logit.
Description
Functions to take the expit and logit of numerical vectors.
Usage
expit(x)
logit(x)
Arguments
x |
vector of real numbers; for |
Details
logit
implements the usual logit function, which is
logit(x) =
\log\frac{x}{1-x},
and expit
its inverse:
expit(x) = \frac{e^x}{1+e^x}.
It is assumed
that logit(0) = -Inf
and logit(1) = Inf
, and correspondingly
for expit
.
Value
A real vector corresponding to the expits or logits of x
Functions
-
logit
: logit function
Warning
Choosing very large (positive or negative) values to
apply to expit
may result in inaccurate inversion (see example
below).
Author(s)
Robin Evans
Examples
x = c(5, -2, 0.1)
y = expit(x)
logit(y)
# Beware large values!
logit(expit(100))
[Package rje version 1.12.1 Index]