'Jitter' (Add Noise) to Numbers (original) (raw)
| jitter {base} | R Documentation |
|---|
Description
Add a small amount of noise to a numeric vector.
Usage
jitter(x, factor = 1, amount = NULL)
Arguments
| 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. |
Details
The result, say r, is r <- x + runif(n, -a, a)where n <- length(x) and a is the amountargument (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 seta <- factor * d/5 where d is the smallest difference between adjacent unique (apart from fuzz) x values.
Value
jitter(x, ...) returns a numeric of the same length asx, but with an amount of noise added in order to break ties.
Author(s)
Werner Stahel and Martin Maechler, ETH Zurich
References
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.
See Also
[rug](../../graphics/html/rug.html) which you may want to combine with jitter.
Examples
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))
[Package _base_ version 4.6.0 Index]