Blog Archives

Deriving a Priority Queue from a Plain Vanilla Queue

November 25, 2013
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Following up on my recent post about implementing a queue as a reference class, I am going to derive a Priority Queue class. Inheritance The syntax for Reference Class inheritance is quite intuitive. We need to modify only two of the methods. The most important of these is insert(), which is where all of the

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Implementing a Queue as a Reference Class

November 24, 2013
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I am working on a simulation for an Automatic Repeat-reQuest (ARQ) algorithm. After trying various options, I concluded that I would need an implementation of a queue to make this problem tractable. R does not have a native queue data structure, so this seemed like a good opportunity to implement one and learn something about

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Iterators in R

November 13, 2013
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According to Wikipedia, an iterator is “an object that enables a programmer to traverse a container”. A collection of items (stashed in a container) can be thought of as being “iterable” if there is a logical progression from one element to the next (so a list is iterable, while a set is not). An iterator

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Introduction to Fractals

November 3, 2013
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Introduction to Fractals

A short while ago I was contracted to write a short piece entitled “Introduction to Fractals”. The article can be found here. Admittedly it is hard to do justice to the topic in less than 1000 words. Both of the illustrations were created with R. Mandelbrot Set The Mandelbrot Set image was created using the

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Percolation Threshold: Including Next-Nearest Neighbours

November 1, 2013
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Percolation Threshold: Including Next-Nearest Neighbours

In my previous post about estimating the Percolation Threshold on a square lattice, I only considered flow from a given cell to its four nearest neighbours. It is a relatively simple matter to extend the recursive flow algorithm to include other configurations as well. Malarz and Galam (2005) considered the problem of percolation on a

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Percolation Threshold on a Square Lattice

October 29, 2013
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Percolation Threshold on a Square Lattice

Manfred Schroeder touches on the topic of percolation a number of times in his encyclopaedic book on fractals (Schroeder, M. (1991). Fractals, Chaos, Power Laws: Minutes from an Infinite Paradise. W H Freeman & Company.). Percolation has numerous practical applications, the most interesting of which (from my perspective) is the flow of hot water through

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R package for effect size calculations for psychology researchers

October 19, 2013
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Dan Gerlanc writes: I read your post the other day on helping psychologists do research and thought you might be interested in our R package, “bootES”, for robust effect size calculation and confidence interval estimation using resampling techniques. The package provides The post R...

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Plotting Times of Discrete Events

October 19, 2013
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Plotting Times of Discrete Events

I recently enjoyed reading O’Hara, R. B., & Kotze, D. J. (2010). Do not log-transform count data. Methods in Ecology and Evolution, 1(2), 118–122. doi:10.1111/j.2041-210X.2010.00021.x. The article prompted me to think about processes involving discrete events and how these might be presented graphically. I am not talking about counts (which are well represented by a

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Applying an Operation to a List of Variables

October 14, 2013
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Just a quick note on a short hack that I cobbled together this morning. I have an analysis where I need to perform the same set of operations to a list of variables. In order to do this in a compact and robust way, I wanted to write a loop that would run through the

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Top 250 Movies at IMDb

October 2, 2013
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Top 250 Movies at IMDb

Some years ago I allowed myself to accept a challenge to read the Top 100 Novels of All Time (complete list here). This list was put together by Richard Lacayo and Lev Grossman at Time Magazine. To start with I could tick off a number of books that I had already read. That left me with around 75

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