**Back Side Smack » R Stuff**, and kindly contributed to R-bloggers)

It is officially no longer pi day, but I didn’t see this Drew Conway post about estimating pi until just a few minutes ago. Because Google Reader doesn’t show github embeds, I also got to try it without seeing Drew’s solution. The estimation method relies on exploiting the area of a circle.

We can use R to generate random numbers for our and coordinates and count up the number of pairs inside the circle (or quarter of a circle, in our case). Because is the area of our quarter circle, the ratio of the 4 times the number of random coordinates within the quarter circle to the total number of random coordinates should converge on . This is a *very* simple Monte Carlo integration. So what do we get?

From pi day |

Gets pretty close! The final error was , not too shabby! I’m computing the running sample average, so it isn’t a true Monte Carlo, but it converges well enough. Code is below:

**leave a comment**for the author, please follow the link and comment on his blog:

**Back Side Smack » R Stuff**.

R-bloggers.com offers

**daily e-mail updates**about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...