Author Archives: Sean

Passwordless SSH on CentOS

The CentOS wiki page misses out a crucial step in setting up passwordless SSH.

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Complex Reflection Groups

After a spring clean I came across a talk I gave on the classification of complex reflection groups back in March 2011.

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Rescan Wireless Networks on Ubuntu

Sometimes I can’t find wireless networks which I know exist (on Ubuntu 16.04). Forcing the wireless interface to rescan fixes the problem. 

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Distribution of Pancake Day

Today is pancake day and it got me thinking about the fact that I remember the day falling on my birthday (March 7th) just once in my lifetime. How long will I have to wait until it next falls on … Continue reading

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Delete large number of jobs with SGE

Sometimes I accidentally add lots of jobs to our SGE queue and want a quick way to delete them.

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Relationship between Car Insurance Price and Population Density

There was some discussion in my office today about the correlation between car insurance prices and where you live. The idea being that the prices are correlated with population density.

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Install G77 on Ubuntu >=14.04

In 2012 I wrote how to install G77 on Ubuntu >=9.04. However that approach no longer works (yet that particular blog posts gets lots of hits because of a link from stackoverflow). So here are some updated instructions which work … Continue reading

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How to Install the Edimax AC600 Wireless Driver for the Raspberry Pi

I use an Edimax AC600 series USB wireless device for my raspberry pi. Here is the easy way to install the driver for it. 

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Number of Unique Song Choices on Desert Island Discs

Desert Island Discs celebrates its 75th birthday today, and today’s guest is David Beckham. Beckham will pick 8 song choices to take away with him on a desert island. What I wondered was, will all of his song choices have been … Continue reading

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Maths on a Mug #16

#mathsonamug pic.twitter.com/Rd0IAC9YHw — Sean Elvidge (@seanelvidge) November 17, 2016 Perhaps a “simple” #mathsonthemug this time. Simple, but very important. This is Bayes’ theorem: \[P(A|B) = \frac{P(B|A)P(A)}{P(B)}.\] This relates the probability of observing \(A\) given that \(B\) is true where \(A\) … Continue reading

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