The latest blog posts to take off on Hacker News. 132 posts.
I was at SCNA the other day, and someone approached me about TDD and Dijkstra’s algorithm. He wondered if you could find a sequence of tests that would lead you to the algorithm. This sounded like a fun little exercise, so I decided to give it a try here.
Definition: The Fibonacci sequence is defined as \(F(0) = 0\), \(F(1) = 1\), and \(F(n) = F(n-1) + F(n-2)\) for \(n ≥ 2\). So the sequence (starting with \(F(0)\)) is 0, 1, 1, 2, 3, 5, 8, 13, 21, ….
Towards deep symbolic reinforcement learning Garnelo et al, 2016 Every now and then I read a paper that makes a really strong connection with me, one where I can’t stop thinking about the imp…
Learn about public engagement activities from the American Physical Society
On another page , I unleash the simulated annealing algorithm on a toy problem. It generates an image full of random colorful pixels, and rearranges the pixels so that similar colors are near each other.
Michael Gove, the UK’s Secretary of State for Education, has expressed a wish to see almost all school pupils studying mathematics in one form or another up to the age of 18. An obvious quest…
I’ve been working on a redesign of this site, so doing more CSS, finally internalizing Sass, etc. During my reading, the nth-child pseudo-class caught my eye.
Posted by Bogdan Arsintescu, Software Engineer & Sreenivas Gollapudi, Kostas Kollias, Tamas Sarlos and Andrew Tomkins, Research ScientistsAlgor...
At first glance, the US highway seems like a jumble of roads: However, the numbers follow a grid, with rules nobody told me (image source, click to enlarge):
Not music nerds, obviously. I don’t know anything about music. I know there are letters but sometimes the letters have squiggles; I know an octave doubles in pitch; I know you can write a pop song with only four chords. That’s about it. The rest has always seemed completely, utterly arbitrary. Why do we have twelve…
MIRI is releasing a paper introducing a new model of deductively limited reasoning: “Logical induction,” authored by Scott Garrabrant, Tsvi Benson-Tilsen,
Join Illya Gerasymchuk on his new blog as he explores blockchain, DeFi, Zero-Knowledge cryptography, AI, and finance.
In the post on matrices in Codea I mentionned that an affine transformation (things like rotation, scaling, translation) ℝ 3 → ℝ 3 could be specified by giving four vectors. In this post I want to examine that a little more closely for the special case of a rotation. That is to say: how can I encode a rotation in ℝ 3…
Its been quite some time since I wrote a Data Mining post . Today, I intend to post on Mean Shift – a really cool but not very well known algorithm. The basic idea is quite simple but the results a…
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Engineering at Forward | UCLA CS '19
Big O notation is a great tool. It allows one to quickly make smart choices among various data structures and algorithms. But sometimes a casualBig O analy...
A little while back I found need of a PNG loader for a small project of mine . Being a complete tool I of course decided to write my own -- after all, why save yourself effort when there are still wheels waiting to be reinvented? You can check the source to the inflater code here if you so like - it's quite cleanly…
Flattening images of curled pages, as an optimization problem.
Around 2006, my friend Dan Christensen created a fascinating picture of all the roots of all polynomials of degree ≤ 5 with integer coefficients ranging from -4 to 4:
Petr Švenda, Matúš Nemec, Peter Sekan, Rudolf Kvašňovský, David Formánek, David Komárek, and Vashek Matyáš, Masaryk University
An image kernel is a small matrix used to apply effects like the ones you might find in Photoshop or Gimp, such as blurring, sharpening, outlining or embossing. They're also used in machine learning for 'feature extraction', a technique for determining the most important portions of an image. In this context the…
My new office space suffers from a shortage of photons, so I’ve been wiring up light fixtures. As I was snaking 14-gauge cable through the ceiling cavity, I began to wonder: Why is it called 14-gauge? I know that the gauge specifies the size of the copper conductors, but how exactly? The number can’t be a simple…
Gradient descent is a standard tool for optimizing complex functions iteratively within a computer program. Its goal is: given some arbitrary function, find a minumum. For some small subset of functions - those that are convex - there's just a single minumum which also happens to be global. For most realistic…
Update! I tested more hash functions in a follow-up post. See More Hash Function Tests .
I recently read “Adventure Time: Volume 1”, a comic book based on the smart animated series of the same name. In the comic, I found some odd looking messages at the …
