Fun with linear transformation in R

Define a simple plotting function:

f = function(m,v) { plot(m,xlim=v[1:2],ylim=v[3:4], col=1:5,pch=16,cex=3, xlab='x',ylab='y') } x = seq(0.1,1.0,0.2) m = cbind(x,x)

Linear transformation as shown above.

limits=c(0,2,0,2) par(mfrow=c(2,2)) f(m,limits) T=matrix(c(2,0,0,2),nrow=2) f(m %*% T,limits)

Rotation of 180°

limits = c(-1,1,-1,1) par(mfrow=c(2,2)) f(m,limits) T=matrix(c(0,-1,-1,0),nrow=2) f(m %*% T,limits)

Rotation by steps

# cex=2 s=1/sqrt(2) T=matrix(c(s,s,-s,s),nrow=2) limits = c(-1.4,1.4,-1.4,1.4) par(mfrow=c(3,3)) f(m,limits) for (i in 1:8) { m = m %*% T f(m,limits)}