January 2012

Project Euler in R: Problem 25

January 24, 2012 | Neha

Solutions in R to Project Euler problems are generally hard to find, so I've recently started posting R solutions on this site.  Here are the previous problems: problem 22, problem 23 and problem 24Now let's... [Read more...]

R Appears Among Top 20 Programming Languages

January 24, 2012 | EpiGrad

Speaking of R… On the 16th, TIOBE Software released the Tiobe Index of the most popular programming languages. For the first time ever, R is in the Top 20. The top spots are, no surprise, occupied by Java and C respectively. More after the jump. The way this index is assembled ... [Read more...]

BBBT Podcast with David Smith

January 24, 2012 | David Smith

Last Friday I was fortunate enough to have the opportunity to travel to Boulder, CO and present R and Revolution Analytics to about 20 analysts as part of the Boulder BI Brain Trust (BBBT). It was a great pleasure to describe the vision for Revolution R Enterprise and got some great ... [Read more...]

It is "simply" the average value

January 24, 2012 | arthur charpentier

for some obscure reasons, simple things are usually supposed to be simple. Recently, on the internet, I saw a lot of posts on the "average time in which you hold a stock", and two rather different values are mentioned "Take any stock in the United ... [Read more...]

Announcing boolean3 (beta)

January 24, 2012 | Jason

After entirely too long, I am happy to announce the beta release of boolean3, an R package for modeling causal complexity. The package can be downloaded at the following links: Unix/Linux: boolean3_3.0.20.tar.gz Windows: boolean3_3.0.20.zip (Please let me know if you have any … Continue reading → [Read more...]

Analyzing US Government Contract Awards in R

January 23, 2012 | Vik Paruchuri

As I was exploring open data sources, I came across USA spending. This site contains information on US government contract awards and other disbursements, such as grants and loans. In this post, we will look at data on contracts awarded in the state of Maryland in the fiscal year 2011, which ... [Read more...]

ACT to SAT M+V Concordance Chart in R

January 23, 2012 | btibert3

For those of who work in Enrollment Management and routinely analyze higher ed data, I wanted to share an easy way to convert ACT to equivalent SAT M+V scores in R. I am dynamically building a dataset that uses the concordance chart located here. Simply, use this data frame ... [Read more...]

New R User Group in Belgium

January 23, 2012 | David Smith

RBelgium is the latest local R user group to join the R community. Led by R user Jean-Baptiste Poullet, the group will host meetings on the first Friday of each month at the Alfot Hotel in Brussels, as well as weekly coffee get-togethers. The group also provides an on-line discussion ... [Read more...]

Flight mapping in R

January 23, 2012 | geotheory.org

This map has been produced before (and much better) by others but who cares. This effort was achieved purely via the standard R plot function*. I believe the only departure from predecessor maps has been to order the list by … Continue reading → [Read more...]

Marketing Mix Lab: Visualising The Correlation Matrix

January 23, 2012 | simonraper

Following on from the previous post here is an R function for visualising correlations between the explanatory variables in your data set. An interesting example is the North Carolina Crime data set that comes with the plm package. This has the following continuous variables: crmrte crimes committed per person prbarr ... [Read more...]

The distribution of financial returns made simple

January 23, 2012 | Pat

Why returns have a stable distribution As “A tale of two returns” points out, the log return of a long period of time is the sum of the log returns of the shorter periods within the long period. The log return over a year is the sum of the daily ... [Read more...]

Starburst in R

January 22, 2012 | Quantitative Doodles

__ starburst('Matrices!') M M M a a a t t t rrr Matrices! ccc e e e s s s ! ! ! wrathematic led me FibBuzz, which led me to Starburst. Now that it’s over, you can see my solution, which uses R matrices. v=strsplit(readLines('stdin'),'')[[1]] d=... [Read more...]

Even odds

January 22, 2012 | arthur charpentier

This evening, I found a nice probabilistic puzzle on http://www.futilitycloset.com/ "A bag contains 16 billiard balls, some white and some black. You draw two balls at the same time. It is equally likely that the two will be the same color as diff... [Read more...]

Some Rcpp benchmarks

January 22, 2012 | Shige

I ran the Fibonacci number example from the Rcpp package on a number of computers and operating systems. Here are the results:A. On my main computer (Core 2 Extreme 3.06GHz, 8 GB memory) running Ubuntu 10.04 (g++ 4.4.3):        test... [Read more...]
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