jitter

R Base 3.6.2

Add a small amount of noise to a numeric vector.

Syntax

jitter(x, factor = 1, amount = NULL)

Arguments

Parameter	Description
`x`	numeric vector to which jitter should be added.
`factor`	numeric.
`amount`	numeric; if positive, used as amount (see below), otherwise, if = 0 the default is factor * z/50. Default (NULL): factor * d/5 where d is about the smallest difference between x values.

Return Value

jitter(x, …) returns a numeric of the same length as x, but with an amount of noise added in order to break ties.

Details

The result, say r, is r <- x + runif(n, -a, a) where n <- length(x) and a is the amount argument (if specified). Let z <- max(x) - min(x) (assuming the usual case). The amount a to be added is either provided as positive argument amount or otherwise computed from z, as follows: If amount == 0, we set a <- factor * z/50 (same as S). If amount is NULL (default), we set a <- factor * d/5 where d is the smallest difference between adjacent unique (apart from fuzz) x values.

Examples

Example

# NOT RUN {
round(jitter(c(rep(1, 3), rep(1.2, 4), rep(3, 3))), 3)
## These two 'fail' with S-plus 3.x:
jitter(rep(0, 7))
jitter(rep(10000, 5))
# }