thechao

16 ms·

211.
by thechao 1y ago
I'll double-reply, since I think people might also appreciate this... there's a pretty easy way to find the square of 2-leading-digit numbers (and square-roots, too.) Direct square: 54^2 = (50 + 4)^2 = 2500 + 2 * 50 * 4 + 4^2. Dir
212.
by thechao 1y ago
These are both great! I learned most of these old tricks from my dad & grandfather.
213.
by thechao 1y ago
I don't know about powers-of-10; but, you can use something similar to bootstrap logs-in-your-head. So, 2^10=1024. That means log10(2)~3/10=0.3. By log laws: 1 - .3 = 0.7 ~ log10(5). Similarly, log10(3)*9 ~ 4 + log10(2); so, log10
214.
by thechao 1y ago
The grade system we implemented was a little program: you can pass the class if you get a passing grade on your HW and tests (weighted average); if you fail either HW or exams, you get the lower of the two.
215.
by thechao 1y ago
Just in case any else is wondering: there are only 83 right-truncatable primes (RTP) and that is it . There's two constraints that let you see this "immediately": 1. An RTP must start with {2,3,5,7,9}; and, 2. An RTP must en
216.
by thechao 1y ago
You could... ? Or, it can just be what it is: addressable from "share". That has the nice property that if she gets a copy of notes from friends, or the internet, it's not "built in": it uses the functionality alrea
217.
by thechao 1y ago
Given that it's summer-break and school is not the top of their thoughts, they're actually pretty thrilled. Here's what my youngest did: she took her hand-copied notes (from the book), took a photo with her camera, highlighte
218.
by thechao 1y ago
I really like this. I'm going to grab some of my kiddos 7th grade biology notes (handwritten), and see what it does. I did notice that's it's a little hard to manage your deck: removing and shuffling are not obvious?
219.
by thechao 1y ago
Not nesting: the ability (for a little while) to tell slack to locally reorder the conversation. This tends to happen with three users all trying to talk to each other: the communication is still dual, so you end up with "yeahs" a
220.
by thechao 1y ago
One thing I like about Slack-like message systems is that they naturally bottom post. However, they tend to go "asynchronous", which makes conversiarcheology nearly impossible. I don't understand why I can't click the me
221.
by thechao 1y ago
I'm reading through your paper, and I really like your ideas. I just think you're approaching the engineers wrong.
222.
by thechao 1y ago
My problem with your interaction on this forum, so far, is that it kind of ignores the practical (artisan) craft of programming. The use of static type systems by working engineers isn't math ; it's more akin to "fast, forma
223.
by thechao 1y ago
This looks like you've defined the abstract lattice extension as a proper superset of the concrete semantics. That sort of analysis is entirely subsumed by Cousot & Cousot's work, right? Abstract Interpretation doesn't re
224.
by thechao 1y ago
Todd Veldhuizen — of C++ template metaprogramming (in)fame(y) — had a paper called "Parsimony Principles in Software Programming" or something like that. His argument was that libraries should be built in decomposable layers. The
225.
by thechao 1y ago
In 2025, for sure. In 2009 ... maybe? Of course, he had become set in his ways in the 80s and 90s.
226.
by thechao 1y ago
When I was being taught assembly at Intel, one of the graybeards told me that the greatest waste of an integer was to use it for a "bare" add, when it was a perfectly acceptable 64-wide vector AND. To belabor the the point: he use
227.
Dead Stars Don’t Radiate(johncarlosbaez.wordpress.com)
246 points by thechao 1y ago|148 comments
228.
by thechao 1y ago
I've talked to my rep about the idea of "credit card cancellation": the idea that you should be able to go through your bank (or you credit card provider's web app) go to a recurring charge and click "cancel" f
229.
by thechao 1y ago
Ironically, the website broke, and became stuck on the "rw[one_is_succ_zero]" rewrite rule, continually telling me that "rfl" isn't valid. Sigh.
230.
by thechao 1y ago
I used to try to convince the faculty at a stodgy Texas University to let me name courses (this was Texas A&M's Dept of CS); your course? "Baguettes and Baudelaire". My suggestion for the programming language course &quot
231.
by thechao 1y ago
I showed up to the C++ rodeo right as C++98 was taking off, and got to work with Jaakko & Gaby & Bjarne (at TAMU) on what would be C++11 (C++0x). Man — those were great times. I still can't decide which craziness — reflection o
232.
by thechao 1y ago
I suspect, that in the context of "reputable academically sound Egyptologist" the number "6" is a bumper crop of Egyptologists. The set of reputable academics in these fields is always a lot smaller than you'd like.
233.
by thechao 1y ago
[ ] Onion Article Title [ ] Act of Congress
234.
by thechao 1y ago
I'm in the US, so you'll have to forgive my ignorance, here, but isn't the UK's tax law pretty tightly unified at the federal level? I once got into an argument with the county (Travis, Texas) over how to account for a p
235.
by thechao 1y ago
Understood, but the heat pump, itself, depreciates. They're good for about 10 years, out here, so you'd have to knock 900$/yr off the "investment". That takes it down to 6%, which is better than a high yield savings
236.
by thechao 1y ago
Me: What is the tallest tree in Texas? CGT: The tallest tree in Texas is a 44 foot tall tree in ... Me: No it's not! The tallest tree is a pine in East Texas! CGT: You're right! The tallest tree in Texas is probably a Loblolly Pin
237.
by thechao 1y ago
I just went down the rabbit hole of ATC hiring policy: you can't be hired before 18 (given the educational requirements, this is impossible in practice, anyways); but must be hired before you turn 30. You face mandatory retirement at
238.
by thechao 1y ago
There's an enormous premium on heat pumps in the U.S. So, there's a manufacturer of heat pumps here, in Austin; they sell a heat pump for 1600$ in Australia (installed); but the same unit is 9000$ (installed) in Austin. Part of th
239.
by thechao 1y ago
Hold on, let me translate my stupid freedom units into Science™. My exterior house walls are already ... 30cm thick? That's 15cm of insulation + structure, a thermal gap, and then 10cm of stone facade. I only have to run the AC for a f
240.
by thechao 1y ago
The compromise is to defeat gerrymandering. It has the nice quality of being constitutional. Most policies I've seen for defeating gerrymandering don't pass constitutional muster. I say this as someone who worked in the antigerrym

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