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Early-February flotsam

February 7, 2012
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Early-February flotsam

Mike Croucher at Walking Randomly points out an interesting difference in operator precedence for several mathematical packages to evaluate a simple operation 2^3^4. It is pretty much a divide between Matlab and Excel (does the later qualify as mathematical software?) … Continue reading →

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What’s new in futile.paradigm 2.0.4

February 6, 2012
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What’s new in futile.paradigm 2.0.4

Well this certainly took a while but the latest installment of my functional dispatching library for R is finally released …Continue reading »

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General Bayesian estimation using MHadaptive

February 6, 2012
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General Bayesian estimation using MHadaptive

If you can write the likelihood function for your model, MHadaptive will take care of the rest (ie. all that MCMC business). I wrote this R package to simplify the estimation of posterior distributions of arbitrary models. Here’s how it works: 1) Define your model (ie the likelihood * prior). In this example, lets build

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Multiple Factor Model – Building Fundamental Factors

February 4, 2012
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Multiple Factor Model – Building Fundamental Factors

This is the second post in the series about Multiple Factor Models. I will build on the code presented in the prior post, Multiple Factor Model – Fundamental Data, and I will show how to build Fundamental factors described in the CSFB Alpha Factor Framework. For details of the CSFB Alpha Factor Framework please read

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"R": PLS Regression (Gasoline) – 003

February 3, 2012
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"R": PLS Regression  (Gasoline) – 003

The gasoline data set has the spectra of 60 samples acquired by diffuse reflectance from 900 to 1700 nm. We saw how to plot the spectra in the previous post.Now, following the tutorial of Bjorn-Helge Mevik published in "R-News Volume 6/3, August 2006", we will do the PLS regression:gas1 <- plsr(octane~NIR, ncomp = 10,data = gasoline, validation...

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Monty Hall by simulation in R

February 3, 2012
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Monty Hall by simulation in R

(Almost) every introductory course in probability introduces conditional probability using the famous Monte Hall problem. In a nutshell, the problem is one of deciding on a best strategy in a simple game. In the game, the contestant is asked to select one of three doors. Behind one of the doors is a great prize (free

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speed of R, C, &tc.

February 2, 2012
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speed of R, C, &tc.

My Paris colleague (and fellow-runner) Aurélien Garivier has produced an interesting comparison of 4 (or 6 if you consider scilab and octave as different from matlab) computer languages in terms of speed for producing the MLE in a hidden Markov model, using EM and the Baum-Welch algorithms. His conclusions are that matlab is a lot

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"R": Plotting the spectra (Gasoline) – 002

February 2, 2012
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"R": Plotting the spectra (Gasoline) – 002

"R" has a package called "ChemometricsWithR", where we can get data from different analytical instruments including Near Infrared (NIR).Follow the steps to plot the spectra of a gasoline data set:In this other case we plot the spectra of the NIR shootout 2002: > data(shootout)> wavelengths<-seq(600, 1898,by=2)> mattplot(wavelengths,shootout$calibrate.1,xlab="wavelength(nm)",ylab="log1/R)")>...

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R Chart featured in Facebook IPO

February 2, 2012
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R Chart featured in Facebook IPO

Page 7 of Facebook's 213-page S-1 filing for their record-breaking IPO includes the following chart, under the headline: "Our Mission: To make the world more open and connected". This chart was created using the R language and Hadoop by Facebook intern Paul Butler. (Thanks to the blog IOER Tools for first noticing the inclusion of the chart.) And speaking...

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tenured research position with ABC skills!

February 2, 2012
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tenured research position with ABC skills!

I just received this announcement for the opening of a (tenured/civil servant) position in the national research institute in biostatistics, genetics, and agronomy, INRA: Position opening with profile Approximate inference techniques in complex systems Key activities and required skills: You will develop methodological research in the field of statistical inference for models used in environmental

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