That's impressive, but not as impressive as this: <a href="https://twitter.com/InternetH0F/status/1721641836404408536" rel="nofollow noreferrer">https://twitter.com/InternetH0F/status/1721641836404408536</a>
Squinting at this, I wonder if it's at all valid to say that the existence of a quadratic time algorithm to calculate pi has anything to do with the fact that the implicit formula of a circle is made up of quadratic terms.<p>In other words, if pi basically sums up the most important fact about a circle's geometry, then it's reasonable to expect that geometry to be represented somehow in the important facts about algorithms that calculate pi.
I think an earlier version of this algorithm was implemented as a showcase in one of the corman lisp for windows 16bit examples folder. I was astonished watching it print thousands of digits of pi in under a minutes.<p>edit: it was just atan <a href="https://github.com/sharplispers/cormanlisp/blob/master/examples/pi.lisp">https://github.com/sharplispers/cormanlisp/blob/master/examp...</a>
I thought we only had algorithms to do this in hexadecimal or other power-of-2 bases. Looks like arbitrary bases including base 10 have been doable since 1996!