incdiff: Increase difference

In AkselA/R-ymse: Ymse (Various)

Description

Rearrange a sorted numeric sequence so that the difference between subsequent elements is increased

Usage

incdiff(x, step = 2)

Arguments

x	a numeric sequence
step	how long a step the difference is considered for.

Details

With step=2 (default) only the difference between immediate neighbours are considered; the difference between every second element will remain small, or rather reduced, compared to the original sequence. With step=3 say, differences of both lag 1 and 2 is increased, but the difference of lag 1 will be less than if a step of 2 was used.

Examples

x <- 1:100
diff(x)

diff(incdiff(x, 2))
diff(incdiff(x, 3))

diff(incdiff(x, 2), 2)
diff(incdiff(x, 3), 2)

# incdiff will introduce a periodicity equal to the step length
acf(incdiff(x, 10))

# useful for making a sequence of colours more distinct
y <- seq(0.4, 1, l=18)
cols1 <- hsv(y, 1, y)
cols2 <- hsv(y, 1, incdiff(y, 3))

plot(y, col=cols1, pch=16, cex=5, ylim=c(0.4, 1.5))
points(y+0.5, col=cols2, pch=16, cex=5)

AkselA/R-ymse documentation built on March 21, 2020, 9:52 a.m.