February 2012

Exponential smoothing and regressors

February 28, 2012 | Rob J Hyndman

I have thought quite a lot about including regressors (i.e. covariates) in exponential smoothing (ETS) models, and I have done it a couple of times in my published work. See my 2008 exponential smoothing book (chapter 9) and my 2008 Tourism Management paper. However, there are some theoretical issues with these approaches, ... [Read more...]

Project Euler in R: Problem 26

February 27, 2012 | Neha

I have been posting R solutions to Project Euler problems as a way of polishing my R skills. Here is the next problem in the series, problem 26. The problem is stated as follows:A unit fraction contains 1 in the numerator. The decimal representati... [Read more...]

PCA for NIR Spectra_part 005: "Reconstruction"

February 27, 2012 | jrcuesta

We saw how to plot the raw spectra (X), how to calculate the mean spectrum, how to center the sprectra (subtracting the mean spectrum from every spectra of the original matrix X). After that we have developed the PCAs with the NIPALS algorithm, getting...
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RHadoop updated: improved performance and more control

February 27, 2012 | David Smith

Revolution Analytics' open-source RHadoop project, which provides integration between R and Hadoop, has been updated with the release of version 1.2 of the "rmr" package. New in this version: support for binary I/O formats, which improves on the text-only interfact by allowing use of faster and more space-efficient data formats ... [Read more...]

Revolution Analytics at Strata 2012

February 27, 2012 | David Smith

One of my favourite conferences, Strata: Making Data Work, starts tomorrow in Santa Clara, CA. Revolution Analytics is a proud sponsor, and I'll be there with the team to listen to some great talks and to meet other R users at our booth in the exhibition hall. There will be ... [Read more...]

Subsetting made easy

February 27, 2012 | Gregor

Calculating characteristics such as median, mean,… of a subset of data is quite straightforward in R: For a data set containing results from several “models”, a subset for the model “base” is created by Then, the median of the variable … Continue reading → [Read more...]

Realized efficient frontiers

February 27, 2012 | Pat

A look at the distortion from predicted to realized. The idea The efficient frontier is a mainstay of academic quant.  I’ve made fun of it before.  This post explores the efficient frontier in a slightly less snarky fashion. Data The universe is 474 stocks in the S&P 500.  The predictions ... [Read more...]

Show me the data! Or how to digitize plots

February 27, 2012 | Markus Gesmann

I had mentioned the Guardian's data blog and the need for more data journalism earlier here. What I really like about the Guardian's approach in particular is that they share the data of their articles and encourage readers to use it.Of course there ar...
[Read more...]

The R-Podcast Episode 2: Getting Ready to Use R

February 26, 2012 | The R-Podcast

In this episode: A couple of site updates, our first listener feedback, an overview of installing R on each major platform, and an overview of R IDEs and helpful resources for getting started with R. If you would like to provide feedback, please send an email or audio comment to ... [Read more...]

Music player in R (Linux)

February 26, 2012 | sachaepskamp

Yesterday I found out about ‘mplayer’, which is a movie/music player for Unix that can be completely controlled from the terminal (http://www.mplayerhq.hu/). I started playing around with it while at the same time learning reference classes. The result, a music … Continue reading → [Read more...]

Sensual marimba sunspots

February 25, 2012 | Ethan Brown

Here's the numbers of yearly sunspots, 1700-1988, brought to you by the nimble marimba of R: See ?sunspot.year in R for more information about the data. I did this last spring and just discovered it again. I've been so caught up in the current sound world of playitbyr (see ... [Read more...]
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