The winds of Winter [Bayesian prediction]

Posted in Books, Kids, R, Statistics, University life with tags , , , , , , , , , , on October 7, 2014 by xi'an

A surprising entry on arXiv this morning: Richard Vale (from Christchurch, NZ) has posted a paper about the characters appearing in the yet hypothetical next volume of George R.R. Martin’s Song of ice and fire series, The winds of Winter [not even put for pre-sale on amazon!]. Using the previous five books in the series and the frequency of occurrence of characters’ point of view [each chapter being told as from the point of view of one single character], Vale proceeds to model the number of occurrences in a given book by a truncated Poisson model,

$x_{it} \sim \mathcal{P}(\lambda_i)\text{ if }|t-\beta_i|<\tau_i$

in order to account for [most] characters dying at some point in the series. All parameters are endowed with prior distributions, including the terrible “large” hyperpriors familiar to BUGS users… Despite the code being written in R by the author. The modelling does not use anything but the frequencies of the previous books, so knowledge that characters like Eddard Stark had died is not exploited. (Nonetheless, the prediction gives zero chapter to this character in the coming volumes.) Interestingly, a character who seemingly died at the end of the last book is still given a 60% probability of having at least one chapter in  The winds of Winter [no spoiler here, but many in the paper itself!]. As pointed out by the author, the model as such does not allow for prediction of new-character chapters, which remains likely given Martin’s storytelling style! Vale still predicts 11 new-character chapters, which seems high if considering the series should be over in two more books [and an unpredictable number of years!].

As an aside, this paper makes use of the truncnorm R package, which I did not know and which is based on John Geweke’s accept-reject algorithm for truncated normals that I (independently) proposed a few years later.

Posted in Books with tags , , , , , , , on April 13, 2014 by xi'an

Posted in Books with tags , , , , , , on March 23, 2014 by xi'an

Broken Blade & King of Thorns [book reviews]

Posted in Books with tags , , , on March 1, 2014 by xi'an

Over the past few weeks, I read Broken Blade by Kelly McCullough, the start to a series of novels taking place in a fantasy universe and involving the same characters. As in many recent novels I read, the main character Aral Kingslayer is more an anti-hero, not very congenial and rather drawn towards booze and self-loathing. He is one of the last remaining Assassins of a religion which goddess got killed (with very little explanations on how and why this happened). Maybe this is a good enough explanation for his current psychological state, hence the “broken” in the title, but that does not make him more endearing! The story itself is more of a sleuthing one, Aral acting as the detective for hire and another character as the client seeking to recover her inheritance. (With the more unusual add-ons of ghouls and zombies and magics. And the more usual theme of corrupted police officers.) Nothing earth-shattering and still a pleasant ride (that made me miss my metro station once!). As an indicator of how I liked it, I already ordered the sequel Bared Blade. If only to see whether the novelty does wear out… Or not!

About a year ago, I mentioned reading Lawrences’s Prince of Thorns and being rather uneasy about the central anti-hero, a 14-year old at the head of a gang of murderers and worse. I nonetheless bought the second volume, King of Thorns, a few months ago. Once again, I am unhappy about the lack of moral and basic compassion of Jorg and found it difficult to trudge through the ethic morass that King of Thorns represents… In some sense, the character gets more depth and some minimal type of humanity, but most of his actions do not make sense and the added touch of Indiana Jones at some crucial point in the story is just annoying. And I am usually adverse at the mix of science-fiction and fantasy in vague post-apocalyptic universes.  Not recommended, despite the flow of highly positive reviews…

the painted man

Posted in Books, Kids, Travel with tags , , , , , on June 9, 2012 by xi'an

Another of those fantasy books I bought on the spur of the moment, without prior information, and that I ended liking very much! Indeed, when I was in the UK in April, I bought a few books for my son in Fort William, of all places!, and The painted man by Peter Brett was one of them. My son got very enthusiastic about it and read it within a few days. Then kept asking about the sequel… (Note that the book strangely has an alternative title in the US, The warded man. With the same so-so cover. Why?! Because UK readers could not understand the word warded?! Because US readers would think The painted man was about American indians?!)

So I took the book with me to Guérande to see how good this was and I got hooked as well, finishing it in three days. The sequel, The Desert Spear, is already sitting on top of the to-read-pile! The central theme of the book(s) is a variation on the “fear of the dark” theme, when darkness is full of real dangers, also found in, e.g., Sanderson’s Mistborn series or Terry Goodkind’s (rather annoying) Wizzard’s First Rule or yet Barbara Hambly’s mosy enjoyable (if older) Darwatch trilogy. And, of course, the forerunner H.G. Wells’ Time Machine where morlocks feed upon elois… Not a very promising start, then, especially when the three main characters are three (pre-)teenagers embarking upon their own quest and of course doomed to meet at some point in the story. However, Brett manages to turn this classic in the genre into something different and highly gripping. One of the attractions of the story is that the demons (or corelings) that come out of the ground when the sun sets down are not described into painful details, only their deadly power matters and it seems so overwhelming that the notion of fighting them does not make sense, either to the inhabitants of this universe or to the reader. When one character, Arlen, decides to, nonetheless, it is a major surprise (mild spoiler warning!) that he survives the first night, the first month and then the whole book! Although there are several deus ex machina interventions to make this possible, the story flows rather nicely and Arlen turns into the major character in the book, Further, his growing powers against the night demons come at the price of distancing himself from the other people and (stronger spoiler warning!) getting more similar to the beings he obsessively pursues. Which is why the other characters are destined to meet him. And help him recover his humanity.

Of course, this is not a perfect book. Besides the recurrence of happenstance moments, some characters are too caricatural. For instance, as in several recent fantasy novels (Richard Morgan’s Cold Commands to just pick one!), one desert-related part of the world follows an Islamic-type culture that carries all the clichés about Muslim countries. This makes the book sounds quite ethno-centric, with the bigoted and superstitious but good at heart communities from the North getting the better part over the fanatic, sexists and untrustworthy denizens of the South. I am actually afraid the second volume The Desert Spear will see more of this simplistic opposition as the southern desert tribes start an invasion very much reminding me of the Muslim invasions of the 7th and 8th centuries… The female character, Leesha, is also rather inconsistent, from strong to weak to strong again, a flaw in the story, esp. against the much more coherent Arlen. But, all in all, this remains a terrific first book and many readers seem to have felt the same way from the mostly positive reviews on line. I am eagerly waiting to get my Desert Spear back so that I can read it!