Thanks to everyone who visited and commented here at R-Chart over the last year! Blogging has forced me to crystallize my thoughts and I hope others have benefited a bit from these meanderings. It it great to interact with the&nbs...

The last puzzle of the year in Le Monde reads as follows (as far as I understand its wording!): Iter(n,x,y) is the function Iter=function(n,x,y){ if (n==1){ output=trunc(y/10)+x*(y%%10) }else{ output=Iter(n-1,x,Iter(1,x,y))} return output } Find the seven-digit number z such that Iter(6,1,z)=12, Iter(6,2,z)=19, Iter(6,3,z)=29, and Iter(6,-1,z)=Iter(6,-2,z)=Iter(6,-3,z)=0. Obviously, the brute-force solution of listing all 90 million seven digit

The blog year started in August and consists of 30-something posts. Here is a summary. Quant concepts backtesting: Backtesting — almost wordless cointegration: American TV does cointegration efficient frontier: Anomalies meet volatility implied alpha: Implied alpha — almost wordless portfolio theory: Ancient portfolio theory random walk: The tightrope of the random walk returns: A tale … Continue reading...

Following Ashley’s latest comments on Chapter 5 of Introducing Monte Carlo Methods with R, I realised Example 5.5 was totally off-the-mark! Not only the representation of the likelihood should have used prod instead of mean, not only the constant should call the val argument of integrate, not only integrate uses lower and upper rather than

Ashley put the following comment on Chapter 5 of Introducing Monte Carlo Methods with R”: I am reading chapter 5. I try to reproduced the result on page 128. The R codes don’t work on my laptop. When I try to run the following codes on page 128 > for (i in 1:(nlm(like,sta)$it)){ + mmu=rbind(mmu,nlm(like,sta,iter=i)$est)}

There was a small earthquake in northern England on Tuesday. Barry Rowlingson felt the quake (it rattled the photographs on his wall), but didn't know how big of a quake it was because he didn't know how close he was to the epicentre. The British Geological Survey hadn't yet announced the quake, but did give access to seismograph readings,...

Pierre Jacob and I got this email from a student about our parallel Rao-Blackwellisation paper. Here are some parts of the questions and our answer: Although I understand how the strategy proposed in the paper helps in variance reduction, I do not understand why you set b=1 (mentioned in Section 3.2) and why it plays

My sabbatical is rapidly coming to an end, and I have to start thinking more and more about teaching. Glancing over my module description for the introductory computational statistics course I teach, I noticed that it’s a bit light on recommend/background reading. In fact it has only two books: A first course in statistical programming

This week Google announced its Ngram Viewer, which allows you to explore the use of words in thousands of texts overtime, going back two hundred years. Given the relatively long time period covered by this massive data set, it is fun to explore how language has changed overtime. Some texts, however, seem to transcend time.