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The most popular blog posts about math & algorithms on Hacker News. 107 posts.
I remember seeing once the following photo from Flickr, and having my brain melt slightly from trying to figure out what went wrong: The issue was the propeller was rotating as the camera detector 'read out', i.e. there was some motion during the exposure of the camera. This is an interesting thing to think about…
Notes will appear here. Please view in Chrome or Firefox. Chrome is glitchy, Firefox is stuttery. Work in progress. :/
This article is now available in Japanese: 紙と鉛筆でビットコインをマイニング：1日に0.67ハッシュ and Russian: Майним Bitcoin с помощью бумаги и ручки . I decided...
Clever student: I know! $latex x^{0}$ = $latex x^{1-1}$ = $latex x^{1} x^{-1}$ = $latex \frac{x}{x}$ = $latex 1$. Now we just plug in x=0, and we see that zero to the zero is one! Cleverer …
This post is about an idea I had around 1997, when I was 16 years old and a freshman computer-science major at Cornell. Back then, I was extremely impressed by a research project called CLEVER, wh…
Intel’s manuals for their x86/x64 processor clearly state that the fsin instruction (calculating the trigonometric sine) has a maximum error, in round-to-nearest mode, of one unit in the last place…
What is an algorithm ? It’s a sequence of steps that you follow to solve a problem. In everyday life, you might have an algorithm for hangin...
Developers take garbage collection for granted, but it's hard to see how it works. Watch 5 different GC algorithm visualizations.
Author’s note: this article used to be called “What Every ComputerProgrammer Should Know About Floating Point, part 1”. Some peoplenoted that this was perh...
This post is inspired by the “metacademy” suggestions for “leveling up your machine learning.” They make some halfway decent suggestions for beginners. The problem is, thes…
Recently, there’s been a great deal of excitement and interest in deep neural networks because they’ve achieved breakthrough results in areas such as computer vision. 1
As a guest today in my daughter’s second-grade classroom, full of math-enthusiastic seven-and-eight-year-old girls, I led a mathematical investigation of graph coloring, chromatic numbers, ma…
People often ask me "What good is Relativity?" It is a commonplace to think of Relativity as an abstract and highly arcane mathematical theory that has no consequences for everyday life. This is in fact far from the truth.
About a week ago, Randall Munroe published Frequency , the 1331st entry in his xkcd webcomic series. Unlike most xkcd comics, it's animated — actually, 5-by-10 grid of animated GIFs. Each describes a scenario (e.g., "one birth," or "someone locks their keys in their care") and blinks at the scenario's purported…
The notion of standard deviation has confused hordes of scientists; it is time to retire it from common use and replace it with the more effective one of mean deviation. Standard deviation, STD, should be left to mathematicians, physicists and mathematical statisticians deriving limit theorems. There is no scientific…
A couple of Sundays ago, I wrote an implementation of Dijkstra’s algorithm in Clojure. The core algorithm came to twenty-five lines. I banged out the code as...
A tale of numbers that like to turn: a different look at complex numbers and the strange things they do.
It’s a huge surprise, and shows up in the most unlikely of places!
The Fermi Paradox: There should be 100,000 intelligent alien civilizations in our galaxy — so why haven't we found any of them?
Recently, after being awake for longer than I should have, I started thinking about methods of remembering the number of days in each month of the year. There is a rhyme for it, and a way to count on your knuckles, but these didn’t satisfy me. I wondered if there was a mathematical formula for the problem, and upon…
An explanation of how walking through walls would actually look like if you could move in 4D.
