Monthly Archives: April 2012

Using bigmemory for a distance matrix

April 7, 2012
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Using bigmemory for a distance matrix

The process of working on metadata and temperature series gives rise to several situations where I need to calculate the distance from every station to every other station. With a small number of stations this can be done easily on the fly with the result stored in a matrix. The matrix has rows and columns

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Newton’s Method In R

Here is a toy example of implementing Newton’s method in R. I found some old code that I had written a few years ago when illustrating the difference between convergence properties of various root-finding algorithms, and this example shows a … Continue reading →

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What are the distributions on the positive k-dimensional quadrant with parametrizable covariance matrix? (solved)

April 7, 2012
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What are the distributions on the positive k-dimensional quadrant with parametrizable covariance matrix? (solved)

Paulo (from the Instituto de Matemática e Estatística, Universidade de São Paulo, Brazil) has posted an answer to my earlier question both as a comment on the ‘Og and as a solution on StackOverflow (with a much more readable LaTeX output). His solution is based on the observation that the multidimensional log-normal distribution still allows

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Writing reproducibly in the open with knitr

April 7, 2012
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Writing reproducibly in the open with knitr

Sweave is something of a gold standard in reproducible research. It creates a dynamic document, written in a mix of LaTeX and R code where the results of the analysis (numbers, figures, tables) are automatically generated from the code and inserted into the resulting pdf document, making them easy to update if the data or

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An R programmer looks at Julia

April 7, 2012
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In January of this year I first saw mention of the Julia language in the release notes for LLVM. I mentioned this to Dirk Eddelbuettel and later we got in contact with Viral Shahregarding a Debian package for Julia. There are many aspects of Julia tha...

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Writing reproducibly in the open with knitr

April 7, 2012
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Writing reproducibly in the open with knitr

Sweave is something of a gold standard in reproducible research. It creates a dynamic document, written in a mix of LaTeX and R code where the results of the analysis (numbers, figures, tables) are automatically generated from the code and inserted in...

Read more »

Temperature Change in Ireland

April 7, 2012
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Temperature Change in Ireland

Has Ireland gotten any warmer? Ask any punter on the street and they will happily inform you of wild swings, trends and dips. “Back when I was a child”, “when I was younger”, or “years ago” are the usual refrains. What’s the evidence? To answer this, I will use the temperature data from my previous

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Install R 2.15 and further versions in Debian Squeeze

April 6, 2012
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The last Friday, March 30th, the last stable version of R, the version 2.15.0 was released.So, to install it in Debian Squeeze, or in another Distro powered by Debian (I actually use CrunchBang Linux), just follow the same instructions described here f...

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The race for speed at the data layer

April 6, 2012
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The competition amongst database vendors to create the fastest, most powerful "data layer" — the hardware and software to provide storage for Big Data with high-performance data processing — is clearly heating up. The Netezza appliance has been so successful that IBM has been racing to keep up with demand. SAP is also seeing success with its HANA in-memory...

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RNA-Seq Methods & March Twitter Roundup

April 6, 2012
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There were lots of interesting developments this month that didn't work their way into a full blog post. Here is an incomplete list of what I've been tweeting about over the last few weeks. But first I want to draw your attention to the latest manuscri...

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