Previously I wrote about latin squares and set a puzzle. Can we make a latin square where all possible pairs are represented in adjacent squares? We can demonstrate this for an n x n latin square where n = 12 In the above images, the normalised latin square only has 12 different pairs out of […]
Category: computing
In Circles: fitting a circle to a curve
A comment from a referee led me to find a method to describe curvature of membranes. This is a quick write-up of our solution. I couldn’t find a solution readily available in Fiji, so I created one using a combination of Fiji for tracing the curvature and IgorPro to do the fitting. If there is […]
I’ve Gotta Get A Message To You II: fixing SSMTP gmail authorisation
This is a ultra-short post related to sending email via the command line on Linux/Rasperry Pi. On 30 May 2022, Google disabled the handy feature that allowed less secure sign in to Google accounts. This feature was a handy way to authenticate command-line routines that send email. I noticed my daily emails had stopped, and […]
Weather Report: building a weather station
As a project idea for a young engineer we wanted to build a Raspberry Pi-based Weather Station. Our last attempt at building something – a sound-responsive LED display – was a failure. So it was important to build something really easy to help us get back on track. Here are some notes. We essentially followed […]
Latin Quarter: Colours and Latin Squares
I read about aesthetic uses of Latin Squares on John Cook’s site a few months ago. Since I maintain a resource to use colour tables in Igor Pro, I thought it would be fun to use Latin Squares to display colour tables for easy visualisation. Briefly, I wrote some code to generate a 9 x […]
Tips From The Blog XVII: determining playback speed of a video
Generating movie files for publication can be a bit tricky. We have a protocol for making them for microscopy data, which simplifies things. However, we recently got this question from a journal: please state the playback speed of each movie file How can we do this? What information is needed for movie files? Usually movies […]
Fixing a hole: reinstalling pi-hole
I run two pi-holes on my home network (details here). The older of the two was in need of a refresh. Here are some notes on how I did a reinstall. For those that don’t know, a pi-hole is a simple ad-blocking solution. You can donate to the project here. Problem The pi-hole itself can […]
Tips From The Blog XVI: fast check of two directories
Here is a quick method for checking parity between two directories. Let’s say we have two directories dir1 and dir2. They are large and have thousands of files and subdirectories. How can we check that they have the same contents? I found myself in this situation recently during a server migration. Method 1: rsync To […]
Line Up: Waffle plots for colocalisation data
Quantifying the degree of colocalisation of two signals in microscopy images is very tricky. Lots has been written on this topic, including in my book The Digital Cell. The focus of this post is on visualising colocalisation. One way to look at colocalisation is two think about two sets of objects and how many of […]
Seles II: Tennis coding challenge solution
In a previous post, I described a coding challenge sent to me by my colleague. Here is the challenge again: There is a tennis match between two players denoted 1, and 2. You are given a sequence of 1s and 2s whereby each number denotes a point won by player 1 or player 2 (e.g. […]