March 2012

digest 0.5.2

March 15, 2012 | Thinking inside the box

A new version of the digest package (which generates hash function summaries for arbitrary (and possibly nested) R objects using any of the standard md5, sha-1, sha-256 or crc32 algorithms) is now on CRAN. Murray Stokely noticed a corner case where... [Read more...]

A No BS Guide to the Basics of Parallelization in R

March 15, 2012 | wrathematics

What is parallelization?Parallelization is using multiple processing cores to, hopefully, make your programs run faster than serial code, which is the use of just one processing core. Parallel code is not always faster than its serial counterpart (but if you're doing it right and you're careful about what you ... [Read more...]

p curves revisited

March 15, 2012 | Thom Baguley

I finally found some time to take a closer look at p curves. I haven't had a chance to follow-up my simulations (and probably won't for a few weeks if not months), but I have had time to think through the ideas the p curve approach raises based on some ... [Read more...]

R gotcha for the week

March 15, 2012 | nsaunders

I use the biomaRt package from Bioconductor in almost every R session. So I thought I’d load the library and set up a mart instance in my ~/.Rprofile: On starting R, I was somewhat perplexed to see this error message: Twitter to the rescue. @hadleywickham told me to load ... [Read more...]

Europe most dangerous cities

March 15, 2012 | Eran

When I was searching for data about U.S prison population, for another post, I run across eurostat, a nice source for data to play around with. I pooled some numbers, specifically homicides recorded by the police. A panel data for … Continue reading → [Read more...]

SAP integrates R with HANA

March 15, 2012 | David Smith

We can add SAP to the list of vendors offering R integration with their products. InformationWeek reports that the new SAP BusinessObjects Predictive Analysis model provides a graphical user interface to R. Created in reaction to "competitive and market forces, including the momentum of open source R", the new module ... [Read more...]

Liking of apples – some data to link

March 15, 2012 | Wingfeet

I browsed through a paper by Peneau et al. (J. Sensory Studies, 2007) where they have nice data on apples; consumer evaluation, sensory evaluation and instrumental measurements. I think these are interesting data to examine if these variable blocks can...
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The Anachronism Machine: The Language of Downton Abbey

March 15, 2012 | David Smith

I've recently become hooked on the TV series Downton Abbey. I'm not usually one for costume dramas, but the mix of fine acting, the intriguing social relationships, and the larger WW1-era story make for compelling viewing. (Also: Maggie Smith is a treasure.) Despite the widespread criticial acclaim, Downton has ... [Read more...]

Opinions Not Backed by Money Updated Again

March 15, 2012 | klr

Strange that I am updating this post for a third time and nothing really has changed, but the fact that nothing has changed is incredibly interesting to me.  Since it is an update, I will not duplicate the explanation, so please read the last vers...
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Project Euler: Problem 16

March 15, 2012 | MK

215 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.What is the sum of the digits of the number 21000?Handling large numbers or rather, very large numbers, can be a pain at times. But have no fear, for GMP is here.GMP  makes the s... [Read more...]

Call for chapters: Data Mining Applications with R

March 15, 2012 | Yanchang Zhao

Data Mining Applications with R A book to be published by Elsevier http://www.RDataMining.com/books/book2 Proposal Submission Deadline: April 30, 2012 Introduction R is one of the most widely used data mining tools in scientific and business applications, among dozens of commercial … Continue reading → [Read more...]

Ideas on A Really Fast Statistics Journal

March 15, 2012 | Yihui Xie

I was writing comments on the blog post A proposal for a really fast statistics journal, and I realized the comment box was too small to write down my ideas. I like the proposal a lot, and I feel really bad about the current model of submitting and rev... [Read more...]

R and Hadoop: Step-by-step tutorials

March 14, 2012 | David Smith

At the recent Big Data Workshop held by the Boston Predictive Analytics group, airline analyst and R user Jeffrey Breen gave a step-by-step guide to setting up an R and Hadoop infrastructure. Firstly, as a local virtual instance of Hadoop with R, using VMWare and Cloudera's Hadoop Demo VM. (This ... [Read more...]

AQP / soilDB Demo: Dueling Dendrograms

March 14, 2012 | dylan

Previously, soil profile comparison methods from the aqp package only took into account horizon-level attributes. As of last week the profile_compare() function can now accommodate horizon and site-level attributes. In other words, it is now possible t... [Read more...]

Plotting individual growth charts

March 14, 2012 | heuristicandrew

This R code draws individual growth plots as shown in “Applied Longitudinal Data Analysis: Modeling Change and Event Occurrence” by Judith D. Singer and John B. Willett, an excellent book on multilevel modeling and survival analysis. This code recreates figure … Continue reading → [Read more...]

R code for p curves

March 14, 2012 | Thom Baguley

I have finally got around to posting the R code for my p curve simulation. Those familiar with R will realize how crude it is (I've been caught up with other urgent stuff and had no time to explore further).You are welcome to play with (and improve!) t... [Read more...]

Portfolio Optimization: Specify constraints with GNU MathProg language

March 14, 2012 | systematicinvestor

I have previously described a few examples of portfolio construction: Introduction to Asset Allocation Maximum Loss and Mean-Absolute Deviation risk measures 130/30 Portfolio Construction Minimum Investment and Number of Assets Portfolio Cardinality Constraints Multiple Factor Model – Building 130/30 Index (Update) I created a number of helper functions to simplify process of making ... [Read more...]

Scales and transformations in ggplot2 0.9.0

March 14, 2012 | heuristicandrew

Some R code designed for ggplot2 0.8.9 is not compatible with ggplot2 0.9.0, and today the ggplot2 web site has outdated documentation which gives this broken example: Dennis Murphy points to the ggplot2 0.9.0 transition guide from where I derived … Continue reading → [Read more...]
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