241
Introduction to Digital Filters (2024)
INTRODUCTION TO DIGITAL FILTERS WITH AUDIO APPLICATIONS
Most cited
Posts that commenters keep linking to, ranked by how many different people have cited them in Hacker News comments. 494 posts.
242
Using neural networks to solve advanced mathematics equations
Facebook AI has developed the first neural network that uses symbolic reasoning to solve advanced mathematics problems.
243
Are you one of the 10% of programmers who can write a binary search?
There are some programming books that I’ve read from cover to cover repeatedly; there are others that I have dipped into many times, reading a chapter or so at a time. Jon Bentley’s 19…
244
245
Compressing and enhancing hand-written notes (2016)
I wrote a program to clean up scans of handwritten notes while simultaneously reducing file size.
246
The Matrix Calculus You Need for Deep Learning
Most of us last saw calculus in school, but derivatives are a critical part of machine learning, particularly deep neural networks, which are trained by optimizing a loss function. This article is an attempt to explain all the matrix calculus you need in order to understand the training of deep neural networks. We…
247
Unsupervised sentiment neuron
Stay up to speed on the rapid advancement of AI technology and the benefits it offers to humanity.
248
249
Eigenvectors from eigenvalues
Peter Denton, Stephen Parke, Xining Zhang, and I have just uploaded to the arXiv the short unpublished note “Eigenvectors from eigenvalues”. This note gives two proofs of a general eige…
250
New pathfinding algorithm
New pathfinding algorithm Oxyd Last week we mentioned the change to make biters not collide with each other, but that wasn’t the only biter-related update we released this past week. Somewhat coincidentally, this week’s updates have included something I’d been working on for a few weeks before – an upgrade to the…
251
Knuth on Huang's Sensitivity Proof: “I've got the proof down to one page” [pdf]
The Sensitivity Conjecture, which I blogged about here, says that, for every Boolean function f:{0,1}n→{0,1}, the sensitivity of f—that is, the maximum, over all 2n input strings x∈{0,1}n, of…
252
Floating Point Visually Explained
While I was writing the Wolfenstein 3D book [1] , I wanted to demonstrate how much of a handicap it was to work without floating points. My attempts at understanding floating points using canonical [2] articles [3] were met with resistance from my brain. I tried to find a different way. Something far from $(-1)^S *…
253
254
The Mathocalypse
More Updates (Oct. 12): Jeffrey Ketchersid has used Claude Code agents to show that BusyBeaver(10) exceeds Graham’s number, beating the previous best result that BB(13) does so. In response t…
255
Regex engine internals as a library
Over the last several years, I’ve rewritten Rust’s regex crate to enable better internal composition, and to make it easier to add optimizations while maintaining correctness. In the course of this rewrite I created a new crate, regex-automata , which exposes much of the regex crate internals as their own APIs for…
256
Cloudflare targets 2029 for full post-quantum security
Recent advances in quantum hardware and software have accelerated the timeline on which quantum attack might happen. Cloudflare is responding by moving our target for full post-quantum security to 2029.
257
258
Introduction to A* (1997)
Movement for a single object seems easy. Pathfinding is complex. Why bother with pathfinding? Consider the following situation:
259
A digestion of the Jacobian conjecture counterexample
The notorious Jacobian conjecture can be formulated concretely over the complex numbers as follows. Conjecture 1 (Jacobian Conjecture) Let $latex {F:{\bf C}^n \rightarrow {\bf C}^n}&fg=000000$ …
260
What every computer programmer should know about floating point, part 1
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...
261
262
Principal Component Analysis Explained Visually (2015)
Principal component analysis (PCA) is a technique used to emphasize variation and bring out strong patterns in a dataset. It's often used to make data easy to explore and visualize.
263
Damn Cool Algorithms: Fountain Codes
Posted by Nick Johnson | Filed under bittorrent , lt-codes , damn-cool-algorithms , fountain-codes
264
The Wavefunction Collapse Algorithm Explained
The Wavefunction Collapse Algorithm teaches your computer how to riff. The algorithm takes in an archetypical input, and produces procedurally-generated outputs that look like it.
265
A Programmer’s Intuition for Matrix Multiplication
What does matrix multiplication mean? Here's a few common intuitions: This is useful when first learning about vectors: vectors go in, new ones come out.…
266
All Hail Geometric Algebra
Rotate a cube by 90 degrees around the \(x\)-axis, then rotate it by 90 degrees around the \(z\)-axis. This is equivalent to a single rotation. What is the axis and angle of this single rotation?
267
268
When Bloom filters don't bloom
Last month finally I had an opportunity to use Bloom filters. I became fascinated with the promise of this data structure, but I quickly realized it had some drawbacks. This blog post is the tale of my brief love affair with Bloom filters.
269
A study of musical scales (2017)
PREFACE. This essay was written in 2009. Since then, a few errata have been corrected and I embedded the youtube videos, but there have been no substantial additions. I think it still holds up fairly well, but if I were to rewrite it today, I would change some things. My main regret is using the criteria of maximum…
270
Teaching Linear Algebra
In a recent Hacker News post I made reference to an interesting teaching experience I had in the mid-90s. This is a longer explanation of ...