this post was submitted on 09 Dec 2023

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Advent Of Code

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[2023 day 8] some guy on reddit manged to brute force part 2 in 57 seconds on a gpu (lemmy.ml)

submitted 11 months ago by [email protected] to c/advent_of_code

16 comments fedilink hide all child comments

https://www.reddit.com/r/adventofcode/comments/18dry49/2023_day_8_part_2glsl_brute_forced_in_under_a/

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[–] [email protected] 12 points 11 months ago

It's a good thing I killed my CPU attempt after 2 hours then!

I would have definitely died in that sandstorm!

[–] [email protected] 4 points 11 months ago (1 children)

I don't know shit about stuff l7ke this, but it's interesting. What does this mean?

[+] [email protected] 4 points 11 months ago* (last edited 11 months ago) (2 children)

[deleted]

[–] coloredgrayscale 1 points 11 months ago (1 children)

One way to get the data is to render to a (hidden) surface/canvas. It's just bytes to the computer, so just dump the result data in the display buffer. Then you take a "screenshot" and interpret the RGBA values as data.

[–] graphicsguy 3 points 11 months ago

Graphics Programmer here.

More likely you would just write data to a buffer (basically an array of whatever element type you want) rather than a render target and then read it back to the cpu. Dx, vulkan, etc. all have APIs to upload / download to / from the GPU quite easily, and CUDA makes it even easier, so a simple compute shader or CUDA kernel that writes to a buffer would make the most sense for general purpose computation like an advent of code problem.

[–] [email protected] 1 points 11 months ago

Thank you!

[–] [email protected] -2 points 11 months ago (1 children)

Brute force what? Part 2 of what?

[–] [email protected] 27 points 11 months ago (1 children)

Erm, do you know where you are?

[–] [email protected] 7 points 11 months ago (1 children)

I can't speak for the other guy, but I definitely don't!

[–] [email protected] 18 points 11 months ago* (last edited 11 months ago) (3 children)

OP is talking about advent of code day 8 part 2 solution. I can't give you details of the problem (because that's just to long) but you're not supposed to brute force the solution because it would take trillions of iterations to get to the right combination.

But the guy in the picture did it anyway.

I forgot to add, you're in the advent of code community so that alone should be enough context to understand OPs post. The questions the other guy asked are the equivalent of going to a formula 1 community and asking "Who the fuck is Toto Wolff and what does Mercedes have to do with anything?"

[–] [email protected] 6 points 11 months ago

What does my auntie Mercedes have to do with anything? I'd like to know too, you know?