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gattr

666 karma · joined December 6, 2017

I like graphics algorithms, astronomy, Rust and Linux.
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gattr··on Planet: Imaging the entire Earth every day
Seems to work fine here (Firefox 68.0, Radeon R370, Fedora 5.2.7-100.fc29.x86_64, KDE/X-Window). That is, I can see the satellites and the rotating globe with strips of land gradually revealed.
gattr··on Anyone who looks at this code instantly becomes insane
So, to avoid people going insane, the code shall be put to refactoring. Each volunteer will only work on a single line of code [0]...

[0] https://en.wikipedia.org/wiki/The_Funniest_Joke_in_the_World

gattr··on Attorney general: Americans should accept security risks of encryption backdoors
Banning open source software is probably not feasible (you can distribute the code as a printed book after all). They would have to:

- ban all Internet traffic that uses non-backdoored encryption (all ISPs would be required to report it)

- ban all amateur radio equipment, including all products one could use to build a satellite dish (like aluminium foil?..); keep a fleet of radio-direction-finding vans circling the streets

Eventually, maybe also ban general-purpose non-backdoored computers.

gattr··on If this type of dark matter existed, people would be dying of unexplained wounds
On a similar note: "How close would you have to be to a supernova to get a lethal dose of neutrino radiation?" [0].

BTW, this happens in the novel "Iron Sunrise" by Charles Stross, where people on an Earth-like planet suffer the misfortune of their star reaching (artificially) the supernova stage.

[0] https://what-if.xkcd.com/73/

gattr··on Intel’s Xeon Platinum 8284 CPU: When 300 MHz Cost $5,500
Of course, my mistake.

I also updated the 1700X to 2700 this year, the "marginality problem" ([0]) affecting some of the early Ryzens (random segfaults after some minutes of heavily parallel workloads with lots of process creation - e.g. builds!) was getting more annoying when Rust needed to download and compile a bunch of crates. I'm very satisfied - more or less the same performance (3.2 vs 3.4 GHz), but 65 W instead of 95 W TDP.

[0] https://www.phoronix.com/scan.php?page=news_item&px=Ryzen-Se...

gattr··on Intel’s Xeon Platinum 8284 CPU: When 300 MHz Cost $5,500
My tangentially related experience: when I switched (after 4 years) from a Core i5-3570K (4C/8T, 3.4 GHz nominal) to a Ryzen 7 1700X (8C/16T, 3.4 GHz nominal) last year, multi-threaded build time of a smallish C++ project I work on went down from 1 minute to 30 seconds.

I'd really like a comparable speed-up on my next HW upgrade; hoping for affordable 16-core CPUs 3-4 years from now.

gattr··on NASA plans to launch a spacecraft to Titan
Associated read: "Titan" by Stephen Baxter. Hard SF describing a manned mission to Titan using present-day level tech; great attention to detail, but be warned that the overall tone is rather depressing.

Myself, I'm absolutely fascinated by the confirmed hydrocarbon lakes and rivers on Titan and can't wait to see actual optical images from up close (so far we only got synthetic-aperture radar images [0]).

[0] https://en.wikipedia.org/wiki/Titan_(moon)#Lakes

gattr··on How Id built Wolfenstein 3D using Commander Keen tech
Interesting point. I can add that it ran smoothly with full-size view on an IBM PS/2 70/80 laptop with a 386SX 20 MHz.
gattr··on Ask HN: What do you do with your Raspberry Pi?
I got a RPi 3B+ to build and test some open-source amateur astronomy tools I contribute to - everything has been working quite nicely so far (I use Fedora on my computers and it also works fine on the Pi). I'm eyeing the RPi 4 with interest.
gattr··on Two potentially life-friendly planets found orbiting a nearby star
As for interesting consequences of a vastly different planetary age: in one SF novel (could be Peter F. Hamilton's, I can't remember right now) humans colonized an Earth-like planet only some 2 billion years old or so. Its uranium ores had so high U235 content (as opposed to Earth's 0.72%, which requires costly enrichment), that you could simply smelt it and put straight in a reactor (cheap nuclear-powered locomotives anyone?).
gattr··on Ways to travel at nearly the speed of light
I absolutely recommend all of these. And of course Reynolds's "House of Suns", which sort of takes the "lighthugger" concept up to eleven.
gattr··on Ask HN: What does your development stack look like in your favorite language?
I've been fully on Linux since 2015. For C, C++ and Rust: Visual Studio Code with appropriate plugins (previously, until ca. 3 years ago - Eclipse). At work we have CLion. For quick editing I'm content with Kate, the text editor bundled with KDE.
gattr··on Wolfenstein: Ray Tracing on Using WebGL1
Actually, you could "mouse look" in the original game, sort of - in addition to looking left/right, moving the mouse up/down would also move the character forwards/backwards.
gattr··on English, Swedish, German and Finnish Decline “Dog” (2013)
Not much to see here, in Polish all the forms (for plural and singular) are just:

pies, psa, psu, psem, psie, psy, psów, psom, psami, psach

gattr··on Input: Fonts for Code
Agreed on the subjectivity. At home (on a 24" 4K monitor) I use Consolas (18 points), at work (on 24" FullHD) I like Ubuntu Mono.
gattr··on I learnt C++ in 2018 and have no regrets
For building my (rather small) projects for Windows I use MSYS2 [0]; it uses pacman for package management and has quite a big library of ready binaries.

[0] http://www.msys2.org/

gattr··on How the Netherlands Feeds the World (2017)
Impressive, to be sure, especially the technical side of things.

However I really dislike greenhouses like these for the huge amount of light pollution they cause (speaking as an amateur astronomer). Sure, it probably doesn't matter much in a densely populated area like the Netherlands, but they start to also pop up here in Eastern Europe, in (previously-) dark-sky locations.

gattr··on Write Your Own Virtual Machine
Is it publicly visible? At the moment in your profile I can only see "about", submissions, comments, favorites.
gattr··on Write Your Own Virtual Machine
I still have the code (old and ugly, so not on GitHub; but it still builds and works) and examples. Let me know where I should send it.
gattr··on Write Your Own Virtual Machine
I agree it's a great exercise. Years ago I added a very simple stack-based VM to my raytracer to allow procedural textures & normal maps. The scene script would e.g. contain a material description like this:

  material {
      diffuse rgb = [0, 0, 1] * (1-(0.5+0.5*noise(x*0.000002, y*0.000002, z*0.000002, 0.66, 2))) + [1, 1, 1] * (0.5+0.5*noise(x*0.000002, y*0.000002, z*0.000002, 0.66, 2));
  }
i.e. an expression with 3-vectors and scalars and a few basic functions (noise, sin/cos, etc.). This can be easily "compiled" (during script parsing) for execution on the VM. Then the overhead during actual raytracing was quite small.
gattr··on Why is nuclear fusion so hard?
Ah, one of my favorite astronomy-related trivia.

It also shows how a supernova can (briefly) shine as brightly as its whole host galaxy (i.e. some 10-11 orders of magnitude stronger than an average dwarf star - like you wrote, those basically "smoulder").

gattr··on International System of Units overhauled in historic vote
And in Dukaj's "Perfect Imperfection" [1] occasionally multiples of Planck time are used (with metric prefixes), as the post-humans and "out-of-space computers" can operate on very small time scales.

[1] https://en.wikipedia.org/wiki/Perfect_Imperfection

gattr··on A Dark Consensus About Screens and Kids Begins to Emerge in Silicon Valley
I remember reading an analysis saying it's the "persistence" features in games that have the strongest potential for addition. E.g. you could play Counter-Strike all night, but the only thing you bring out is your improved skills. Unlike MMORPGs and similar where you "develop the character" and "accumulate equipment" (these days, also for real money).
gattr··on Ask HN: What's your favorite elegant/beautiful algorithm?
I'm into computer graphics, so for me it's raytracing. The principle is simple, so one can quickly code some "shiny spheres" example, but then there's a lot of interesting connected stuff to learn: linear algebra, spatial data structures, Monte Carlo extensions, ...
gattr··on Panspermia
It's interesting to note that, regardless of actual origin of life, a significant exchange might have been occurring (or is still occurring) between Solar System bodies (judging by how we found a number of Martian meteorites on Earth). So if we find life elsewhere in the Solar System, it might be quite compatible.

The idea is mentioned in Kim Stanley Robinson's "2312", where simple organisms exist in Enceladus's ocean, and some people inject them for fun (with neutral or mildly beneficial effects).

gattr··on Boston Dynamics Robots Run, Dance and Flip, But Are They a Business?
Motorized sex-androids also come to mind (remember the articles about the existing ultra-realistic doll makers? the "UI skin" part is already there).
gattr··on Nuclear pasta in neutron stars may be the strongest material in the universe
Seconded.

Likewise, Stephen Baxter's "Flux". (Even crazier, here the lifeforms dwell inside the neutron star, in the neutron superfluid.)

gattr··on Raytracing a Black Hole
And in the coming years astronomers hope to image a black hole directly (in radio wavelengths). The few closest supermassive black holes (in center of galaxies) have their event horizon angular diameters just big enough to be resolved by VLBI (very-long-baseline interferometry). See [3] for details and a simulated image.

[1] https://en.wikipedia.org/wiki/Event_Horizon_Telescope

[2] https://eventhorizontelescope.org/

[3] Seeing Black Holes: from the Computer to the Telescope (https://arxiv.org/pdf/1804.03909.pdf)

gattr··on We know music is pleasurable, the question is why?
Interesting to know what it's called, thanks. I have a few pieces of music that trigger this for me, up to shivers and tears in the eyes (though not at overwhelming/lightning-bolt levels.)

On the other hand, I'm utterly unresponsive to poetry.

gattr··on A First Course in Differential Equations for Scientists and Engineers
On a related note, I can recommend Stanley J. Farlow's "Partial Differential Equations for Scientists and Engineers", which I bought around 2004 to better understand a fluid simulation paper I was trying to implement. (My Maths course ended with linear algebra and ODEs). Very good read with nice physics examples.
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