In “Scalable vector triangulations” I used the svgwrite package to draw the 429 triangulations of an oriented convex nonagon. But there was something unsatisfactory about the size of the resulting image: 1.2 MiB seems rather large for an image which has 3003 triangles and 6435 lines. ( A look at the source reveals three sources of wasted space )

This BBC headline reads “Cambridge cycling: one in three journeys is on a bike.” But is that true? If you actually live and work in Cambridge, and compare the numbers of motor vehicles and cyclists on the roads, or the numbers of car and bicycle parking spaces, that figure does not seem right. Certainly there’s a lot of cycling-more than in any ( Read more... )

When I wrote “The tabular method” I drew a figure showing all the ways to triangulate an oriented convex polygon, from the unique way to triangulate a triangle up to the 14 ways to triangulate a hexagon. I drew it by hand using Inkscape, but I felt there was something unsatisfactory about that: if I can write a program to count the triangulations, ( Read more... )

A lesson I had to learn several times when I worked in video games is that the addition of user options has to be consciously resisted. The desire to add a user option often indicates that you have skimped on a important piece of usability work and are trying to put off doing it. ( Now, you’re probably already saying, “but what about-” at this ( Read more... )

In Vernor Vinge’s 1999 novel A Deepness in the Sky the protagonist learns what it means to become a programmer-archaeologist:

Programming went back to the beginning of time… Behind all the top-level interfaces was layer under layer of support. Some of that software had been designed for wildly different situations. Every so often, the ( Read more... )

Dynamic programming is an important technique for writing combinatorial algorithms, in which you divide a problem into sub-problems, like in good ol’ divide-and-conquer, except that the sub-problems may overlap, so you build up a table of these problems and their solutions in order to avoid repeated work. But the name sucks: the technique is no ( Read more... )

There’s a conventional piece of software development wisdom, to the effect that if writing your own programming language is an absurd and wasteful activity, because developing a programming language is a hideous time-sink, and because some existing language is almost certain to satisfy your needs perfectly well. ( There’s a good deal of truth in ( Read more... )

p4.el, the Emacs/Perforce Integration, provides an interface to the Perforce software version management system from the Emacs text editor. Written originally by Eric Promislow, with important contributions from Rajesh Vaidheeswarran, Peter Österlund, and many others, it’s a piece of software that I have used more or less every day for the last ( Read more... )

This is a problem that had me puzzled for a while, but has a really simple solution, so I’m writing it up here in case it might be useful to other developers who find themselves in this slightly bizarre situation.

Imagine that you are developing a web site using the Django framework. ( The underlying database has been in production for some years ( Read more... )

The very first sentence of Peter F. Hamilton’s Great North Road (2012) reads:

As midnight approached, the wild neon colours of the borealis storm came shimmering through the soft snow falling gently across Newcastle upon Tyne.

How is that possible? Auroras take place high in the sky, in the thermosphere (above 80 km), but if it’s snowing then it ( Read more... )