#!/usr/bin/Rscript
a <- c(2, 10, 1, 5, 8, 4, 5, 8, 7, 5, 6, 4, 2, 2, 4, 9)
dim(a) <- c(2,8)
a <- t(a)
plot(a, col=1:8, pch=19)
text(a[,1]+0.15, a[,2]+0.15, 1:8)
print(dist(a))
print(dist(a) ^ 2)

centers <- a[c(1,4,7),]
step <- 0
while(TRUE)
{
	d <- as.matrix(dist(rbind(a,centers)))[9:11,-(9:11)]
	mapping <- apply(d, 2, which.min)
	cat("step", step, ":\n")
	cat("cluster mappings:\n")
	print(mapping)
	plot(a, col=mapping, pch=19)
	text(a[,1]+0.15, a[,2]+0.15, 1:8)
	cat("centers:\n")
	print(centers)
	points(centers, pch=4, col=1:3)
	Sys.sleep(1)
	new_centers <- t(sapply(1:3, function(i) c(mean(a[which(mapping == i),1]), mean(a[which(mapping == i),2]))))
	if(!sum(new_centers != centers)) break
	centers <- new_centers
	step <- step + 1
}