./backlog: Charlie's blog

meanderings through tidbits of mathsy computery stuff

Marey Christmas

I hate Christmas-time scheduling. It’s a pretty busy time of year and it involves rushing around the country trying to see as many family members as possible. Scheduling this in is really fiddly, as Sophie and I live about 70 miles away from various parts of our families. This means that we have to spend a lot of time trying to figure out the best possible way for us to see as much of our respective families as possible — all while trying to maximise the amount of time that we spend together as a couple as well.

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Getting NVIDIA drivers working on Ubuntu 17.10

I recently upgraded my system from Ubuntu 17.04 (a nice, stable distribution) to 17.10 (a fragile nightmare with very little hardware support). This broke… well, a lot of things. However, the main problem was that my NVIDIA graphics drivers were causing the system to fail to boot. I spent a frustratingly-long time trying to fix this problem on my work machine (NVIDIA 1050Ti graphics card), but I think I’ve finally cracked it.

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Optimisation with Commons Math

This post is about numerical optimisation in Apache Commons Math; more specifically, minimising a special case of a logistic function with some equality constraints (i.e. the solution must be positive and within certain bounds). This post will probably be a bit rough and ready because I’m mostly writing this as an aide-memoire to my future self - but someone else might stumble upon this one day while trying to solve a similar problem, and I hope that it’s useful to them, too.

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My experience working at a cargo cult startup

"In the South Seas there is a Cargo Cult of people. During the war they saw airplanes land with lots of good materials, and they want the same thing to happen now. So they’ve arranged to make things like runways, to put fires along the sides of the runways, to make a wooden hut for a man to sit in, with two wooden pieces on his head like headphones and bars of bamboo sticking out like antennas.

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Fixing the UX of IP Addresses

Remembering IP addresses has long been a pain point for system administrators. They’re long, clunky and difficult to remember - essentially a 12-digit phone number for internet-connected machines. Trying to remember the IPs of the endless reams of servers that you manage (was it x.x.x.y? or was it y.y.y.z?) is difficult - after all, that’s why we have DNS. Trying to remember or communicate all 12 digits (which can be up to 20 syllables long!

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