R: A logit() function robust to values that equal 0 or 1

logitAdj {statisfactory}

R Documentation

A logit() function robust to values that equal 0 or 1

Description

This function returns the logit value (log(x / (1 - x))) where a small value can be added to x to avoid problems of calculating the log when x equals 0 or 1.

Usage

logitAdj(x, epsilon = 0.01, base = 10)

Arguments

`x`	Numeric vector.
`epsilon`	Value to add/subtract from x to ensure log of 0 or 1 is not taken (usually a small number). If `NULL`, then the smallest value of any `x` > 0 and `1 - x` for all `x` < 1 is used.
`base`	Base of logarithm.

Value

Numeric equal to log((x + epsilon)/(1 - x + epsilon), base=base).

Examples


set.seed(123)
x <- seq(0, 1, by=0.01)
logitAdj(x)
logitAdj(x, 0.001)
invLogitAdj(x, 0.001)
invLogitAdj(x, 0.001)
invLogitAdj(x, auto = TRUE)