Add a small amount of noise to a numeric vector.
jitter(x, factor = 1, amount = NULL)
numeric vector to which jitter should be added.
numeric; if positive, used as amount (see below),
= 0 the default is
factor * z/50.
factor * d/5 where
d is about
the smallest difference between
jitter(x, …) returns a numeric of the same length as
x, but with an
amount of noise added in order to break
The result, say
r <- x + runif(n, -a, a)
n <- length(x) and
a is the
argument (if specified).
z <- max(x) - min(x) (assuming the usual case).
a to be added is either provided as positive
amount or otherwise computed from
amount == 0, we set
a <- factor * z/50 (same as S).
NULL (default), we set
a <- factor * d/5 where d is the smallest
difference between adjacent unique (apart from fuzz)
Chambers, J. M., Cleveland, W. S., Kleiner, B. and Tukey, P.A. (1983) Graphical Methods for Data Analysis. Wadsworth; figures 2.8, 4.22, 5.4.
Chambers, J. M. and Hastie, T. J. (1992) Statistical Models in S. Wadsworth & Brooks/Cole.
rug which you may want to combine with