# Monthly Archives: May 2013

## Rmagic, A Handy Interface Bridging Python and R

May 31, 2013
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Rmagic (http://ipython.org/ipython-doc/dev/config/extensions/rmagic.html) is the ipython extension that utilizes rpy2 in the back-end and provides a convenient interface accessing R from ipython. Compared with the generic use of rpy2, the rmagic extension allows users to exchange objects between ipython and R in a more flexible way and to run a single R function or a block

## Snowfall

May 31, 2013
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Yesterday I had a short post reminding EViews users that their package (versions 7 or 8) will access all of the cores on a multi-core machine. I've been playing around with parallel processing in R on my desktop machine at work over the last few days. It's something I've been meaning to do...

## The arteries of the world, in Tweets

May 31, 2013
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What happens when you plot billions of geotagged Tweets on a map? You can see the arteries of the world. Here's Europe: According to creator Miguel Rios (Engineering Manager, Data Visualization at Twitter), the dots on this chart represent every geotagged Tweet since 2009. The color represents number of tweets in the region, and the intensity shows where people...

## Are parallel computations worth it ?

May 31, 2013
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Yesterday, Daniel Marcelino published an interesting post on his blog, untitled Parallel Processing: When does it worth ? I was asking myself the same question for a chapter I am currently writing. And I did like his approach, so I tried, on my computer to do the same. I did use three packages to run parallel R codes, >...

## Regression regularization example

May 31, 2013
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Recently I needed a simple example showing when application of regularization in regression is worthwhile. Here is the code I came up with (along with basic application of parallelization of code execution). Assume you have 60 observations and 50 expla...

## accurate ABC: comments by Oliver Ratman [guest post]

May 31, 2013
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Here are comments by Olli following my post: I think we found a general means to obtain accurate ABC in the sense of matching the posterior mean or MAP exactly, and then minimising the KL distance between the true posterior and its ABC approximation subject to this condition. The construction works on an auxiliary probability

## Version control, gitbucket and SourceTree style

May 31, 2013
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Last time I wrote about version control using Subversion (and its implementation in Eclipse). I still haven’t given up on it, but since I’m using a private repository, sharing code has been a bit tedious. I was introduced to git a while ago, but somehow decided to go for Subversion. A few days ago a

## ”How to draw the line” with ggplot2

May 30, 2013
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In a recent tutorial in the eLife journal, Huang, Rattner, Liu & Nathans suggested that researchers who draw scatterplots should start providing not one but three regression lines. I quote, Plotting both regression lines gives a fuller picture of the data, and comparing their slopes provides a simple graphical assessment of the correlation coefficient. Plotting

## my 1st post for the Guardian Australia

May 30, 2013
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I’ll be contributing a piece about once a week for the Guardian Australia, under a part of the web site we’re calling The Swing. The set of graphs from my 1st effort were rendered in-line and rather low-res. Bigger, full res versions appear below; click on the in-line versions. It would be great to find