Calculating Pi

accuracy.R

attempts <- seq(1000, 1000000, by=10000)
estimated <- sapply(attempts, function(x) calc.pi(make.pi(x)))

ggplot(data.frame(estimated=estimated, n=attempts)) + geom_point(aes(x=n, y=estimated)) + geom_hline(yintercept=pi, color="green")

common.R

library("ggplot2")

set.seed(13)

make.pi <- function(n) {
    darts <- data.frame(x=runif(n), y=runif(n))
    darts$hit <- (darts$x^2 + darts$y^2) <= 1
    darts
}

calc.pi <- function(df) {
    4*sum(df$hit)/nrow(df)
}

visualize.R

sim <- make.pi(10000)
ggplot(sim, aes(x, y, color=hit)) + geom_point() + ggtitle(calc.pi(sim))