Monthly Archives: February 2013

Classifying Emails as Spam or Ham using RTextTools

February 28, 2013
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Recently, I had read an article on R-bloggers, titled Classifying Breast Cancer as Benign or Malignent using RTextTools by Timothy P. Jurka, who is the author of both that article and the RTextTools package. Having reproduced the results using the...

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System Testing

February 28, 2013
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System Testing

R at Work...crunching numbersIf you wanna find out how your trading idea would have coped in the previous years you would perform a backtest. For years I have used commercial software but could not find a package, which I would really recommend. I have...

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The MaxDiff Killer: Rank-Ordered Logit Models

February 27, 2013
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Compared to MaxDiff (Sawtooth Software), ranked-order logit modeling:simplifies data collection without needing additional software to generate experimental designsreduces respondent burden making the task easier and seemingly ...

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inline 0.3.11

February 27, 2013
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A maintenance release of inline is now on CRAN, and is being uploaded to Debian. The release fixes two minor bugs kindly reported by users. As the two previous releases appear to not have been announced here, their NEWS entries are included as well. ...

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The Paul Tol 21-color salute

February 27, 2013
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The Paul Tol 21-color salute

You may or may not know that PerformanceAnalytics contains a number of specific color schemes designed for charting data in R (they aren’t documented well, but they show up in some of the chart examples). I’ve been collecting color palates for years in search of good combinations of attractiveness, relative weight, and distinctiveness, helped along

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Graphical Tools (rgl) on a Headless Shiny Server

February 27, 2013
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If you’ve encountered errors such as Warning in rgl.init(initValue) : RGL: unable to open X11 display Warning in fun(libname, pkgname) : error in rgl_init or Error: rgl_dev_getcurrent when trying to use a graphically based package like RGL with Shiny Server, then you’re in the right spot.  The issue is likely that you’re running R or

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Non-Linear Curve Fitting is Nature Publication Worthy?

February 27, 2013
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Non-Linear Curve Fitting is Nature Publication Worthy?

Someone needs to explain to me why this is a Nature publication ...Granted it is Nature Protocols which started its publication run when I was in grad school and is likely less high-impact as full blown Nature.  Seriously tough - using the So...

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Workshops on Modelling Choices using R in Toronto

February 27, 2013
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Making choices is inherently human. We choose between brands of cereal or amongst candidates in an election. At times, choices may be influenced by the characteristics of the decision maker, such as age, income and sex. Choices may also be influenced by the attributes of competing alternatives, such as the cost of travelling between two cities by air or...

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UPDATE Multiple postgreSQL Table Records in Parellel

February 27, 2013
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UPDATE Multiple postgreSQL Table Records in Parellel

Unfortunately the RpostgreSQL package (I’m pretty sure other SQL DBs as well) doesn’t have a provision to UPDATE multiple records (say a whole data.frame) at once or allow placeholders making the UPDATE a one row at a time ordeal, so I built a work around hack to do the job in parellel.  The big problem

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Resampling data in Hadoop with RHadoop

February 27, 2013
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On Revolution Analytics partner Cloudera's blog, Uri Laserson has posted an excellent guide to resampling from a large data set in Hadoop. Resampling is an important step in fitting ensemble models (including random forests and other bagging techniques), and Uri provides a step-by-step guide to implementing resampling methods using RHadoop. He provides the complete map-reduce code in the R...

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