| jitter {base} | R Documentation |
Add ‘Jitter’ (Noise) to Numbers
Usage
jitter(x, factor=1, amount = NULL)
Arguments
x |
numeric to which jitter should be added. |
factor |
numeric |
amount |
numeric; if positive, used as amount (see below),
otherwise, if Default ( |
Add a small amount of noise to a numeric vector.
jitter(x,...) returns a numeric of the same length as
x, but with an amount of noise added in order to break
ties.
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.
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.
Werner Stahel and Martin Maechler, ETH Zurich
rug which you may want to combine with jitter.
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))
dplot
utilities