For the past couple of days, I had been searching for a tutorial that would show how to create a custom Beamer template. I found some great resources and some really great customized templates (I have listed the ones that I referred to below) but none ... [Read more...]

I really love the plyr package. Apart from having a progress bar and plyr handeling a lot of the overhead, a very interesting feature is being able to run plyr in parallel mode. Essentially, setting .parallel = TRUE runs any… See more › [Read more...]

I just found these two gems about debugging in R on r-help today (here is the thread): 1) posted by Thomas Lumley: traceback() gets you a stack trace at the last error options(warn=2) makes warnings into errors options(error=recover) starts the post-mortem debugger at any error, allowing you to ... [Read more...]

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Kay Cichini recently wrote a word-cloud R function called GScholarScraper on his blog which when given a search string will scrape the associated search results returned by Google Scholar, across pages, and then produce a word-cloud visualisation. This was of interest to me because around the same time I posted ... [Read more...]

I am talking here about money managers. for those of us who have one. We assume they understand about markets in such a way that they can, and will generate at least the benchmark returns, what ever this benchmark may … Continue reading → [Read more...]

(This is a follow-up to my previous post on the topic.)I was encouraged by the appearance of two R-based Scholar-scrapers, within a week of each other. One, by Kay Cichini, converts the page URLs into text mode and scrapes from there (There's a slightl... [Read more...]

Always new software language in one technical activity is difficult, normally a good documentation can help, these are three book to use R software for beginner and for experts: ·         “Introduction to the R Project for Statistical Computing for Use at the ITC” by David Rossiter (PDF, 2010-11-21).·         “R for ... [Read more...]

Some time ago I posted a question in stackoverflow to learn how to produce a multipage SVG file. This is …Continuar leyendo » [Read more...]

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A friend of mine recently published a very interesting article on the pedologic interpretation of asymetric peak functions fit to soil profile data (Myers et al., 2011). I won't bother summarizing or paraphrasing the article here, as the original artic... [Read more...]

My intuition tells me that objects traveling through the air would meet more resistance when there is more moisture in the air. It turns out that my intuition is wrong. It still doesn’t make sense to me but apparently humid … Continue reading → [Read more...]

Filed under: pictures, R Tagged: Le Monde, mathematical puzzle, R [Read more...]

I have become quite a big fan of graphics that combine the features of traditional figures (e.g. bar charts, histograms, etc.) with tables. That is, the combination of numerical results with a visual representation has been quite useful for exploring descriptive statistics. I have wrapped two of my favorites (... [Read more...]

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In my last few posts, I have considered “long-tailed” distributions whose probability density decays much more slowly than standard distributions like the Gaussian.  For these slowly-decaying distributions, the harmonic mean often turns out to be a much better (i.e., less variable) characterization than the arithmetic mean, which is generally ... [Read more...]

     At the onset, this was strictly an excercise of my own curiosity and I didn't imagine writing this down in any form at all. As someone who has done some modelling work in the past, I'm embarrassed to say that I had never fully grasped how one can gauge the ... [Read more...]

R version 2.14 introduced a new package, called parallel. This new package combines the functionality from two previous packages: snow and multicore. Since I was using multicore to parallelise my computations, I had to migrate to the new package and decided to publish some code. Often trading strategies are tested using ... [Read more...]

Here's a cool application of calendar heat maps: runner Andy used R to catalogue his daily running mileage over the last 2+ years: There are lots of ways to chart data like this (a simple time-series chart, for example), but sometimes looking at data in new ways offers fresh perspectives. For ... [Read more...]

Revolution Analytics CTO David Champagne visited Hadoop World 2011 this week, and delivered a presentation on "The Powerful Marriage of R and Hadoop" to a standing-room-only crowd of R and Hadoop enthusiasts. I've included David's slides below: The talk also generated praise on Twitter, for example: David was also interviewed by ... [Read more...]