Wednesday 18 November 2009

The R Project for Statistical Computing

I've been playing with The R Project for Statistical Computing. I quite like it.

Here's a few of the first things I did, just playing around:



x = seq(-pi, pi, by = 0.01)
plot(sin(x), col = rgb(abs(sin(x*3)), 0, 0), cex=.2+3*abs(sin(x)), pch=16)
points(cos(x), pch=16, cex=.5, col = rainbow(length(x)))




n = 10000
breaks = 100
plot_count = 5
cols = rainbow(plot_count)

plot(x = c(), xlim=c(-0,1), ylim=c(0,3), main = "distribution of random sums", xlab = "Sum of N random numbers between 0 and 1/N", ylab = "density")

runifrep = function(n, reps) {
tot = 0;
for (i in 1:reps) {
tot = tot + runif(n)
}
tot/reps;
}
for (i in 1:plot_count) {
a = hist(runifrep(n, i), breaks=breaks, plot=0)
lines(y = a$density, x = a$mids, col = cols[i], pch=3, cex = .1, xlim=c(-4,4), lwd = 3)
}


Note that cex is symbol size, pch is symbol and lwd is line width. http://www.harding.edu/fmccown/R/#misc has a nice list of symbols.

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