Monthly Archives: December 2013

Bubble sorting in R, C++ and Julia: code improvements and the R compiler

December 28, 2013
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In the past few months I have written posts about implementing the bubble sort algorithm in different languages. In the mean while I have gotten some feedback and suggestions regarding improvements to the implementation I made, see the end of… See more ›

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Sundial calculations

December 28, 2013
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Sundial calculations

After experimenting with calculations for what I eventually came to realize were analemma-based sundials (with shadow cast by a vertical pole), I remembered that the common sundial has a wedge as the shadow-maker. A bit of research told me that the wedge is called a gnomon. It is a right triangle with one vertex (the centre vertex, shall...

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Summarising multivariate palaeoenvironmental data

December 28, 2013
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Summarising multivariate palaeoenvironmental data

Ordination methods that yield orthogonal axes of variation are often used to summarise the multivariate data obtained from sediment cores. Usually the first or, less often, the first few ordination axes are taken as directions of change or the main patterns of variance in the multivariate data. There is an oft-overlooked issue with this approach that has the potential...

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Top Songs by Artist on CD102.5 in 2013

December 27, 2013
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Top Songs by Artist on CD102.5 in 2013

In a previous post, I showed you how to scrape playlist data from Columbus, OH alternative rock station CD102.5. Since it's the end of the year and best-of lists are all the fad, I thought I would share the most popular songs and artists of the year, a...

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Quantitative Finance Applications in R

December 27, 2013
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Quantitative Finance Applications in R

by Daniel Hanson, QA Data Scientist, Revolution Analytics Extracting Financial Data from Internet Source Using R (first in a series) Earlier this month, a colleague and I attended a presentation on Computational Finance in R, given by Guy Yollin of the University of Washington Applied Mathematics faculty, at a meeting of the Seattle useR Group. The first among several...

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Parallel processing with short jobs only increases the run time

December 27, 2013
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Parallel processing with short jobs only increases the run time

Parallel processing has become much more important over the years as multi-core processors have become common place. From version 02.14 onwards, parallel processing has become part of the standard R installation in the form of the parallel package. This package… See more ›

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High frequency words in TOEFL

December 27, 2013
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High frequency words in TOEFL

In general, TOEFL(Test of English as a Foreign Language) is not an easy test for Chinese students, including me.  Relatively speaking, the reading section is little easier than the other sections (listening, speaking, writing). Interestingly, when I prepared my TOEFL test, I found that some important words appeared frequently in the mock examination. So I did a … Continue reading...

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Points, Polygons and Power Outages

December 27, 2013
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Points, Polygons and Power Outages

Most of my free coding time has been spent tweaking a D3-based live power outage tracker for Central Maine Power customers (there’s also a woefully less-featured Shiny app for it, too). There is some R associated with the D3 vis, but it’s limited to a cron job that’s makes the CSV files for the sparklines

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Sinterklaas and Santa Claus gave presents

December 27, 2013
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Sinterklaas and Santa Claus gave presents

In December my nice little netbook acquired a shiny new openSUSE 13.1, including all the goodies I might want to use in 2014; R, Stan, Julia and Jags. So here is what you might get when you set up a computer for statistics today.JagsI have been using J...

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Statistics unplugged

December 27, 2013
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Statistics unplugged

How much does statistical software help and how much it interferes when teaching statistical concepts? Software used in the practice of statistics (say R, SAS, Stata, etc) brings to the party a mental model that it’s often alien to students, while being highly optimized for practitioners. It is possible to introduce a minimum of distraction

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