HN user
λ𝑓.(λ𝑥.𝑓(𝑥 𝑥))(λ𝑥.𝑓(𝑥 𝑥))
I had a very similar experience—discovering Stirling numbers of the second kind by solving a computer science problem through brute force, then plugging the results into OEIS, then reverse-engineering an elegant solution to the problem. Fantastic resource.
Converting from Python to TLA+ could be considered a form of denotational semantics. It's a ton of work to model the denotational semantics of even simple computer programs. I imagine an automatic translation of a nontrivial program would be infeasible to work with, but curious if there is active research or progress in this field.
Looks like quarto. The LaTex you saw may have been MathJax.
$ curl -s https://manifestai.com/blogposts/faster-after-all/ | grep generator
<meta name="generator" content="quarto-1.3.450">There's a command-line utility called pixd [1] that generates similar data visualizations on the command line. That said, it only shows static representations of binary data and is not nearly as cool as buredoranna's animated gifs showing filesystem changes over time.
It can be helpful to plot these sorts of pixel arrangements on a Hilbert curve, rather than plotting pixels line by line. I learned this trick from a Ghidra plugin called cantordust [2]. 3blue1brown offers some mathematical intuition for the effectiveness of a Hilbert curve pixel arrangement [3].
[1] https://github.com/FireyFly/pixd
[2] https://inside.battelle.org/blog-details/battelle-publishes-...
Is there a link to the actual legal text of the omnibus resolution? Are FTC resolutions publicly available?
I wasn't able to locate the referenced document after briefly searching the FTC legal library and the regulations.gov website. Apologies if I've missed an obvious link from the press release.
I assume the effectiveness of the tracking dart depends on the suspect not knowing it has been affixed to their vehicle. If they knew, wouldn’t they just pry it off?
If one's bike is stolen in the San Francisco Bay Area, there's a small but significant chance you can find it for sale at the Laney College Flea Market (e.g. [1]).
[1] https://www.reddit.com/r/BAbike/comments/8mmrne/stolen_bike_...
Super interesting! My first reaction is, doesn't the while loop, combined with the conditional predicate of the string comparison, essentially promote the regular expression (finite state automaton) into a context-free expression (pushdown automaton)?
Definitely reminds me a lot of not needing parentheses on an RPN calculator, and the isomorphism between Lisp expressions and Forth expressions.
Have been using ncdu for more than a decade, and recently started using diskonaut for similar purposes. Was looking for a terminal-based treemap visualization for analyzing disk usage and stumbled upon diskonaut, which is exactly that.
I think the images are static, so presumably pre-rendered server-side. The editing & rendering on the individual example pages seems to making an API call to a server, which I think is running this [1].
Seems like they updated the site recently, so figured folks might enjoy some of the new content. It's been a while since I've visited; been using Figma for a lot of what I previously used TikZ for. However, I returned today because I wanted to generate some diagrams from a fairly large spreadsheet, which seemed like a perfect task for TikZ. And to my surprise, there's a ton of new prior art on the site to learn from :)
Reminds me of Conway’s Game of Life, emulated inside Conway’s Game of Life:
They aren’t a record of my thinking process. They are my thinking process. I actually did the work on the paper.
-Richard Feynman
I quite like the FreeBSD src tree, as it comprises both the system kernel as well as the userland applications. The folders are organized similarly to the OS file system hierarchy, which I find helpful for navigating the source tree. I found it accessible to slowly learn how various parts of the OS work under the hood and compound my knowledge faster due to less context shifting, since it’s self-contained in one source tree.
I would start off by learning the Canvas API for HTML/JavaScript [1][2]. All you need is a web browser, no extra software or dependencies (well, maybe just a text editor to edit an index.html file on your Desktop). You can test out snippets from MDN and StackOverflow in your browser’s JavaScript console. Once you have a minimal, working example (e.g., a 512x512 square canvas with a color gradient), start messing around with the code and see how it affects the canvas image. For example, modify the parameters of your loops or flip the loop order of nested loops. Focus on the principles rather than on learning any particular technology. Simpler is better when learning; the “best” production software is not necessarily the best to learn with; don’t forget the Telescope Rule [3]. Once you have a foundation for basic graphics, it will be much easier to learn shaders.
[1] https://codepo8.github.io/canvas-images-and-pixels/
[2] https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API
First read the paper last week, though heard the concept in 2014 from a colleague who implemented it [1] (for fun I assume).
Recently revisited his little demo interested in the parser design; this time re-reading, the translation between Boolean logic expressions and TCP checksum calculations finally clicked for me.
My current mental model of it is coercing a calculator, which “only” performs addition and subtraction, into evaluating complicated conditional logic expressions. Not sure how a category theorist would describe it; is it an equivalence of two different categories (evaluation of logic expressions/abstract syntax trees) <> (bitwise negation & addition on integer arrays which represent Boolean matrices)?
In a practical engineering sense, I like to think the core concepts illustrate performance optimization principles for representing branching code as branch-free code. I think branching code is likely faster evaluating single expressions, but branch free representations could be useful for SIMD vectorization, e.g., to increase throughput for evaluating a large number or stream of expressions (such as evaluating security policy rules against operating system events).
Perhaps this explains the rise in American Express's stock price today. Amex has perhaps the best customer service I've experienced (maybe that says more about me than them :).
While Visa is a card network, Amex is both a network and an issuer. Visa works with issuing banks like Chase, so as a Visa cardholder, you would interface with the bank rather than with Visa when reporting an unrecognized charge.
Given that Amex is an issuer, I could imagine that there might exist more incentives to side with the cardholder versus a merchant for disputes, as compared with a company that operates as a network but not directly as a card issuer.
McMaster-Carr supplies thin-wall chromoly tube [0] suitable for fabricating bicycle frames.
[0] tube is measured by the outer diameter; pipe is measured by the inner diameter
I've been learning color theory recently and also found these resources helpful as well:
Tangential, but manganese steel/mangalloy/Hadfield steel was the first steel to be patented [1]. It hardens in response to impacts and is renowned for it's work-hardening properties.
In addition to having the highest work-hardening properties, manganese steel is probably our toughest material. [2]
[1] https://en.wikipedia.org/wiki/Mangalloy#History
[2] T.B. Jefferson. Metals and How to Weld Them, 2nd Edition. page 255
Why must iOS use WiFi to run critical security updates? I assume it’s a kickback from telecoms to reduce network bandwidth from users with unlimited mobile data plans?
@numpad0 Is it the Chunxiao gas field [1] that you’re thinking of?
If you click the URL bar, then press ctrl-F / cmd-F, browser-native search should work. In my experience, this works around sites that override those keyboard shortcuts in JS to implement custom search functionality.
Ack. I read the article before the 2018 suffix was appended to the link so was initially under the impression that it was a recent article. Was trying to be helpful given they concluded the article by saying they were hiring, and that some minor language adjustments might help them towards that objective. My apologies, definitely not trying to incite controversy.
It seems like a lot of schools and colleges have resorted to employing Orwellian test proctoring services.
If the tests are so easy to cheat, does that hint at the value of the underlying education?
Oh wow no kidding. Was not aware of that. This article [1] seems to be the primary source for that. Also kind of funny that the ThreadX wikipedia page [2] randomly links to Intel Management Engine.
[1] https://ownyourbits.com/2019/02/02/whats-wrong-with-the-rasp...
Posted this because this seems like a genuinely awesome product/service. Curious to learn what other companies are making/selling the metaphoric shovels for the nascent genetic- and bio-engineering industries.
Isn't this a massive copyright infringement on Apple's design?
I'm not a lawyer but I think Xerox had the same question back in '89 [1]. Given Apple's luck in pursuing infringement claims against Microsoft [2], I doubt a copyright suit would be fruitful in this case.
[1] https://www.nytimes.com/1989/12/15/business/company-news-xer...
[2] https://legal.thomsonreuters.com/blog/1988-apple-sues-micros...
Also worth checking out James’s simplified version designed for the Lattice iCE40 [1][2].
[1] https://www.excamera.com/sphinx/article-j1a-swapforth.html
Might enjoy browsing through A Bestiary of Single-File Implementations of Programming Languages [1].