Today I had a great reminder of why I love open source software and why I spend a bit of my time contributing R code to several packages. In the vegan, I had included some code to do an analysis … Continue reading →

Amanda Cox of the New York Times' graphics department recently gave a great presentation to the New Media Days conference in Copenhagen and described how the Times uses data visualizations to reveal patterns, provide context, describe relationships, and even create a sense of wonder about the world. In the video, Amanda demonstrates several of the Times' best interactive visualizations...

Amanda Cox of the New York Times' graphics department recently gave a great presentation to the New Media Days conference in Copenhagen and described how the Times uses data visualizations to reveal patterns, provide context, describe relationships, and even create a sense of wonder about the world. In the video, Amanda demonstrates several of the Times' best interactive visualizations...

The translation of the book Introducing Monte Carlo Methods with R is close to being completed. The copy-editing and page-setting are done, I have received the cover proposal and am happy with it, so it should now go to production and be ready by early January, (earlier than the tentative end of February indicated on

Acceptance-rejection methods This post is based on chapter 1.4 of Advanced Markov Chain Monte Carlo. Another method of generating random variates from distributions is to use acceptance-rejection methods. Basically to generate a random number from , we generate a RN from an envelope distribution , where . The acceptance-rejection algorithm is as follows: Repeat until

This week(end), the Le Monde puzzle can be (re)written as follows (even though it is presented as a graph problem): Given a square 327×327 symmetric matrix A, where each non-diagonal entry is in {1,2,3,4,5} and , does there exist a triplet (i,j,k) such that Solving this problem in R is very easy. We can create

As so often happens these days, a brief post at FriendFeed got me thinking about data analysis. Entitled “So how many retractions are there every year, anyway?”, the post links to this article at Retraction Watch. It discusses ways to estimate the number of retractions and in particular, a recent article in the Journal of

An interesting note was arXived a few days ago by Madeleine Thompson and Radford Neal. Beside the nice touch of mixing crumbs and slices, the neat idea is to have multiple-try proposals for simulating within a slice and to decrease the dimension of the simulation space at each try. This dimension diminution is achieved via