What is the best way to compare the quality of floating-point math libraries (e.g., sin, cos and log)? The traditional approach for evaluating the quality of an algorithm implementing a mathematical function is based on mathematics; methods have been developed to calculate the maximum error between the calculated and ... [Read more...]

As I already did two years ago, in connection with the double degree between UAM and Dauphine, I will give a short graduate course at the Universidad Autonoma de Madrid (UAM). It will be part of the regular fourth year statistics course and will focus on mixtures, as given in ... [Read more...]

[This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your [Read more...]

[This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your [Read more...]

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If you didn’t read the post from yesterday, I urge you to do so, or you won’t get what I’m writing here. http://flyordie.sin.khk.be/2011/04/08/day-19-rgg-s-a-btch/ So, coming back from yesterday, I had a talk with my supervisor who to... [Read more...]

The latest local R user group to join the fold is in St Louis, Missouri. Created by Josh Ulrich, their first meeting is on Monday, April 11. Check the link below for full details and to RSVP. Saint Louis R User Group: Inaugural Meeting [Read more...]

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A  listbox is (as far as i thought) supposed to select one or more items in the list and put them in a variable. Well, not for the rgg listbox. Whatever you select, you’ll get an error.                 &#1... [Read more...]

Once in a while, you embark on what looks like a simple computational procedure only to encounter frustration very early on. “I can’t even read my file into R!” you cry. Step back, take a deep breath and take note of what the software is trying to tell you. ... [Read more...]

Following my earlier post on Buffon’s needle and Bertrand’s paradox, above are four outcomes corresponding to four different generations (among many) of the needle locations. The upper right-hand side makes a difference in the number of hits (out of 1000). The R code corresponding to this generation was made ... [Read more...]

If you'd like to learn more about using the PMML package in R to export statistical models, or if you'd just like to learn more about building predictive models in Revolution R and creating predictions (scores) from them in other applications or in the cloud, I'll be co-presenter on a ... [Read more...]

The more I use it, the deeper I fall in love with ggplot2. I know, some of you have heard me kvel about it ad nauseum (oh, yiddish and latin in one sentence – extra points!). But the graphs really look great, and once you wrap your head around a few ... [Read more...]

Another pure maintenance release, this time of RcppClassic, the package supporting the deprecated older classic Rcpp API defined in the earlier 2005 to 2006 releases, is now on CRAN It contains no new code, but smoothes one or two edges in the buil... [Read more...]

What are the alpha shapes?: “The concept of alpha shapes formalizes the intuitive notion of “shape” for spatial point set data, which occurs frequently in the computational sciences. An alpha shape is a concrete geometric object that is uniquely defined for a particular point set.[...] Alpha shapes are generalizations of ... [Read more...]

Hello again Today I am experiencing something weird. The last days I have been experimenting with the R-scripting nodes from knime and with their templates. But today this happened. The node is executed without errors, but when I try to open the view, [Read more...]

When Peter Diggle gave his “short history” of spatial statistics this morning (I typed this in the taxi from Charles de Gaulle airport, after waiting one hour for my bag!), he started with a nice slide about Buffon’s needle (and Buffon’s portrait), since Julian Besag was often prone ... [Read more...]

I realized I never announced this on the blog, so without further ado.... Rcpp Workshop in Chicago on April 28, 2011 This year's R/Finance conference will be preceded by a full-day masterclass on Rcpp and related topics which will be held on... [Read more...]

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