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teraflop commented on Why is the sky blue?   explainers.blog/posts/why... · Posted by u/udit99
justin_dash · 10 hours ago
For the sunset example then, a natural question (for me) is then why isn't the sky green in the transition from blue sky to red sunset sky?
teraflop · 9 hours ago
Because the color of the sky is determined by a shifting mixture of wavelengths, not a single shifting wavelength.

Basically, the scattering process that "remove" blue from the spectrum also removes green, albeit to a lesser extent. There are some greenish and yellowish wavelengths in the sunset sky, but they're dominated by red, so the overall color appears red or orange.

In order for the sky to look noticeably green, there would have to be something that scattered reds and blues, without significantly absorbing green.

If you try to interpolate between sky-blue and orange using graphics software, the result depends on what "color space" you're using. If your software interpolates based on hue, you might see green (or purple) in the middle. But that's not physically realistic.

A realistic model is to interpolate each wavelength of the continuous spectrum separately. Interpolating in RGB color space is a crude approximation to this. And if you try the experiment, you'll see that the midpoint between sky-blue and orange is a kind of muddy brown, not green.

teraflop commented on Converting a $3.88 analog clock from Walmart into a ESP8266-based Wi-Fi clock   github.com/jim11662418/ES... · Posted by u/tokyobreakfast
teraflop · 10 hours ago
Cool project!

The most interesting part, IMO, is the "SRAM with EEPROM backup" chip. It allows you to persistently save the clock hands' positions every time they're moved, without burning through the limited write endurance of a plain old EEPROM. And it costs less than $1 in single quantities. That's a useful product to know about.

teraflop commented on Claude’s C Compiler vs. GCC   harshanu.space/en/tech/cc... · Posted by u/unchar1
o175 · 20 hours ago
The 158,000x slowdown on SQLite is the number that matters here, not whether it can parse C correctly. Parsing is the solved problem — every CS undergrad writes a recursive descent parser. The interesting (and hard) parts of a compiler are register allocation, instruction selection, and optimization passes, and those are exactly where this falls apart.

That said, I think the framing of "CCC vs GCC" is wrong. GCC has had thousands of engineer-years poured into it. The actually impressive thing is that an LLM produced a compiler at all that handles enough of C to compile non-trivial programs. Even a terrible one. Five years ago that would've been unthinkable.

The goalpost everyone should be watching isn't "can it match GCC" — it's whether the next iteration closes that 158,000x gap to, say, 100x. If it does, that tells you something real about the trajectory.

teraflop · 19 hours ago
The part of the article about the 158,000x slowdown doesn't really make sense to me.

It says that a nested query does a large number of iterations through the SQLite bytecode evaluator. And it claims that each iteration is 4x slower, with an additional 2-3x penalty from "cache pressure". (There seems to be no explanation of where those numbers came from. Given that the blog post is largely AI-generated, I don't know whether I can trust them not to be hallucinated.)

But making each iteration 12x slower should only make the whole program 12x slower, not 158,000x slower.

Such a huge slowdown strongly suggests that CCC's generated code is doing something asymptotically slower than GCC's generated code, which in turn suggests a miscompilation.

I notice that the test script doesn't seem to perform any kind of correctness testing on the compiled code, other than not crashing. I would find this much more interesting if it tried to run SQLite's extensive test suite.

teraflop commented on The first sodium-ion battery EV is a winter range monster   insideevs.com/news/786509... · Posted by u/andrewjneumann
Flavius · a day ago
Retaining 90% range at -40°C sounds like a game changer, almost too good to be true. I'm definitely going to need to see some third-party real-world range tests to validate those claims before getting too excited.
teraflop · a day ago
Note that this article's summary has a significant error compared to the original press release[1]. The article says "90% range", whereas the press release says "90% capacity retention".

This is a big difference because there are all kinds of other factors besides energy capacity that can affect the efficiency of the whole system, and therefore affect range.

Most notably, air is about 28% denser at -40°C than at 25°C, so drag is about 28% higher. So you would expect roughly 28% less range at high speeds even if the battery has no capacity loss whatsoever.

As someone else mentioned, climate control also consumes a lot more power when it has to maintain a larger temperature difference between inside and outside.

[1]: https://www.catl.com/en/news/6720.html

teraflop commented on First Proof   arxiv.org/abs/2602.05192... · Posted by u/samasblack
blenderob · 2 days ago
> I.e. a solution is known, but is guaranteed to not be in the training set for any AI.

Not a mathematician and obviously you guys understand this better than I do. One thing I can't understand is how they're going to judge if a solution was AI written or human written. I mean, a human could also potentially solve the problem and pass it off as AI? You might say why would a human want to do that? Normal mathematicians might not want to do that. But mathematicians hired by Anthropic or OpenAI might want to do that to pass it off as AI achievements?

teraflop · 2 days ago
Well, I think the paper answers that too. These problems are intended as a tool for honest researchers to use for exploring the capabilities of current AI models, in a reasonably fair way. They're specifically not intended as a rigorous benchmark to be treated adversarially.

Of course a math expert could solve the problems themselves and lie by saying that an AI model did it. In the same way, somebody with enough money could secretly film a movie and then claim that it was made by AI. That's outside the scope of what this paper is trying to address.

The point is not to score models based on how many of the problems they can solve. The point is to look at the models' responses and see how good they are at tackling the problem. And that's why the authors say that ideally, people solving these problems with AI would post complete chat transcripts (or the equivalent) so that readers can assess how much of the intellectual contribution actually came from AI.

teraflop commented on It's 2026, Just Use Postgres   tigerdata.com/blog/its-20... · Posted by u/turtles3
vagab0nd · 4 days ago
I recently started digging into databases for the first time since college, and from a novice's perspective, postgres is absolutely magical. You can throw in 10M+ rows across twenty columns, spread over five tables, add some indices, and get sub-100ms queries for virtually anything you want. If something doesn't work, you just ask it for an analysis and immediately know what index to add or how to fix your query. It blows my mind. Modern databases are miracles.
teraflop · 4 days ago
I don't mean this as a knock on you, but your comment is a bit funny to me because it has very little to do with "modern" databases.

What you're describing would probably have been equally possible with Postgres from 20 years ago, running on an average desktop PC from 20 years ago. (Or maybe even with SQLite from 20 years ago, for that matter.)

Don't get me wrong, Postgres has gotten a lot better since 2006. But most of the improvements have been in terms of more advanced query functionality, or optimizations for those advanced queries, or administration/operational features (e.g. replication, backups, security).

teraflop commented on LICENSE: _may be_ licensed to use source code; incorrect license grant   github.com/mattermost/mat... · Posted by u/MallocVoidstar
zem · 7 days ago
I am honestly flabbergasted that his pictures weren't expunged with great prejudice. what is the value they add to wikimedia that makes being associated with this sort of sleaze okay?
teraflop · 7 days ago
If you read the discussion, they weren't kept because of their encyclopedic value, or because they were "widespread". I'm not sure why the parent commenter said that.

They were kept to preserve a record of their having been uploaded, and to not create a legal risk for third parties who might be relying on the Commons page as their way to provide attribution.

The original proposal was to keep the image pages with the metadata, but delete the image files. That turned out to have some technical hurdles, so instead the images were overwritten with versions containing big ugly attribution messages, to discourage their use.

teraflop commented on Did a celebrated researcher obscure a baby's poisoning?   newyorker.com/magazine/20... · Posted by u/littlexsparkee
pickleRick243 · 12 days ago
> And if there's no chance of a conviction, there's no benefit to anybody from reopening the investigation.

It's probably true that without a chance of conviction, standard protocol dictates that public resources should not be expended on reopening the investigation. But I was also heavily distracted while reading the article, scanning optimistically for the happy (under the circumstances) ending where justice is served. I certainly don't think there is "no benefit to anybody".

teraflop · 12 days ago
Serious question: if the chance of evidence leading to a convistion is very very small, what would be the benefit of opening an investigation? Just to go through the motions on principle? And what would they even investigate?
teraflop commented on Did a celebrated researcher obscure a baby's poisoning?   newyorker.com/magazine/20... · Posted by u/littlexsparkee
Morizero · 12 days ago
> A toxicological screening of the “white curdled material” had detected codeine but not morphine. But Koren had claimed that the gastric contents “exhibited high morphine” levels—with no mention of codeine—“ruling out administration of Tylenol-3 to the baby.”

> “I don’t know what happened in that house, on that night, but I do know that someone gave this baby crushed Tylenol-3,” likely mixed in breast milk or formula. “That’s the only way these numbers make sense.”

Does no one care that this is potentially a murder case?

teraflop · 12 days ago
I'd guess that everybody involved (including the coroner's office) tacitly understands that even if the baby was deliberately or negligently killed, there's very little chance after 20 years of finding evidence of who did it, in order to demonstrate guilt beyond a reasonable doubt. And if there's no chance of a conviction, there's no benefit to anybody from reopening the investigation.

The scientific case about infant opioid poisoning in general is a separate issue, of course. But assigning blame in this particular case doesn't have any bearing on that.

teraflop commented on Notice of collective action lawsuit against Workday, Inc.   workdaycase.com... · Posted by u/mooreds
SpaceNoodled · 14 days ago
It sounds like you're saying we should generate more bullshit to justify bullshit.
teraflop · 14 days ago
They said "could", not "should".

I believe the point is that it's much easier to create a plausible justification than an accurate justification. So simply requiring that the system produce some kind of explanation doesn't help, unless there are rigorous controls to make sure it's accurate.

u/teraflop

KarmaCake day16657September 22, 2010View Original