Blog Archives

Arrogance sampling

January 7, 2011
By
Arrogance sampling

A new posting on arXiv by Benedict Escoto on a simulation method for approximating normalising constants (i.e. evidence) with an eye-catching name! Here is the abstract This paper describes a method for estimating the marginal likelihood or Bayes factors of Bayesian models using non-parametric importance sampling (“arrogance sampling”). This method can also be used to

Read more »

a survey on ABC

January 6, 2011
By
a survey on ABC

With Jean-Michel Marin, Pierre Pudlo and Robin Ryder, we just completed a survey on the ABC methodology. It is now both arXived and submitted to Statistics and Computing. Rather interestingly, our first draft was written in Jean-Michel’s office in Montpelier by collating the ‘Og posts surveying new ABC papers! (Interestingly because this means that my

Read more »

Short review of the R book

January 5, 2011
By
Short review of the R book

David Scott wrote a review of Introducing Monte Carlo Methods with R in the International Statistical Review that is rather negative, since the main bulk reads as follows: I found some aspects of the book very disappointing. The first chapter (“Basic R Programming”) has some unfortunate mistakes and some statements, which are contentious at least

Read more »

Adap’skiii [day 2]

January 5, 2011
By
Adap’skiii [day 2]

Another exciting day at Adap’skiii!!! Yves Atchadé presented a very recent work on the fundamental issue of estimating the asymptotic variance estimation for adaptive MCMC algorithms, with an intriguing experimental observation that a non-converging bandwidth with rate 1/n was providing better coverage than the converging rate. (I always found the issue of estimating the asymptotic

Read more »

Le Monde puzzle [52|solution]

January 1, 2011
By
Le Monde puzzle [52|solution]

I have now received the first issue of Le Monde magazine, including the solution to puzzle #52 I solved just in time by simulated annealing! The trick is in using the following theorem: Iter(1,x,y) is divisible by 10x-1 if and only if y is divisible by 10x-1. Then the value to be found is divisible

Read more »

History makes Stat. Science!

December 31, 2010
By
History makes Stat. Science!

While the above heading sounds like a title in reverse, its words are in the “correct” order in that our paper with George Casella, A Short History of Markov Chain Monte Carlo, has been accepted for publication by Statistical Science. This publication may sound weird when considering that the paper is also scheduled to appear

Read more »

Le Monde puzzle [52]

December 31, 2010
By
Le Monde puzzle [52]

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

Read more »

More typos in Chapter 5

December 29, 2010
By
More typos in Chapter 5

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

Read more »

nlm [unused argument(s) (iter = 1)]

December 28, 2010
By
nlm [unused argument(s) (iter = 1)]

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)}

Read more »

Poster at MCMSki III

December 28, 2010
By
Poster at MCMSki III

Here is the poster presented at MCMSki III next week by Pierre Jacob about our joint paper on parallelisation: Filed under: R, Statistics, Travel Tagged: Adapski, MCMC, MCMSki, Metropolis-Hastings, Monte Carlo Statistical Methods, parallelisation, pos...

Read more »