Donut math: how donut.c works

[Update 1/13/2021: I wrote a follow-up with some optimizations. ] There has been a sudden resurgence of interest in my “donut” code from 2006, and I’ve had a couple requests to explain this one. It’s been five years now, so it’s not exactly fresh in my memory, so I will reconstruct it from scratch, in great detail, and hopefully get approximately the same result. This is the code: k;double sin() ,

[mumei-0]

数Ⅲ+C の行列を思い出す……