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dfbrown commented on We pwned X, Vercel, Cursor, and Discord through a supply-chain attack   gist.github.com/hackermon... · Posted by u/hackermondev
dfbrown · 6 days ago
Their collaborator's report includes a more significant issue, an RCE on a mintlify server: https://kibty.town/blog/mintlify/
dfbrown commented on Gemini AI   deepmind.google/technolog... · Posted by u/dmotz
milesward · 2 years ago
dfbrown · 2 years ago
How real is it though? This blog post says

In this post, we’ll explore some of the prompting approaches we used in our Hands on with Gemini demo video.

which makes it sound like they used text + image prompts and then acted them out in the video, as opposed to Gemini interpreting the video directly.

https://developers.googleblog.com/2023/12/how-its-made-gemin...

dfbrown commented on 'Do Not Split': A Hong Kong protest film [video]   fieldofvision.org/do-not-... · Posted by u/lawrenceyan
tasogare · 5 years ago
dfbrown · 5 years ago
"The orders instruct him to not make public any information that would identify A.B., or the medical professionals involved, to call A.B. by the child’s preferred name and gender pronoun, and to not share his opinions of the case publicly."

"In June 2020, C.D. gave an interview to a YouTube channel, where he’s alleged to have identified health-care providers, revealed information about A.B.’s mental health, medical status or treatments, and gave out information that could reveal C.D., A.B. and the mother’s identity."

"“This order should not restrict C.D.’s right to express his opinion in his private communications with family, close friends and close advisors, provided none of these individuals is part of or connected with the media or any public forum, and provided C.D. obtain assurances from those with whom he shares information or views that they will not share that information with others,” the court said."

It sounds like his arrest is more due to him repeatedly discussing the case in public rather than the pronouns he used.

https://nationalpost.com/news/b-c-father-arrested-held-in-ja...

dfbrown commented on NPhysics: 2D and 3D Real-Time Physics Engine for Rust   nphysics.org/... · Posted by u/ArtWomb
ghusbands · 6 years ago
> It does CCD

Intersection and post-correction still seems to be present (and the sponge/spring behaviour) in demos even when you increase CCD steps and enable sub-stepping. Look at how much the bottom cubes/spheres intersect when the stack lands. (It's hard to tell what the demo called CCD is demonstrating.)

> intersections / collisions aren't the only dynamic in such a simulation.

Fair. (Contact points and friction also seemed more stable/realistic in Carmageddon 2 than in most physics libraries.)

dfbrown · 6 years ago
There are two separate things here, interpenetration due how contacts/constraints are solved, and whether you do continuous collision sub-stepping or not.

For stability and performance reasons physics engines usually have parameters that soften or add compliance to contacts/constraints. A bit of compliance is almost always better than infinitely stiff collisions/constraints. There are cases where infinitely stiff systems either have no solution, are very expensive to solve, or would produce very extreme impulses (causing things to explode). Including some compliance fixes these issues. It is also often required to produces more realistic looking results since objects in real life aren't infinitely stiff, they either flex or break.

For performance reasons most physics engines also do not completely solve their constraints. They either use a fixed number of iterations (most common, including the demos here) or solve up to some specified error threshold. This tends to add some additional compliance to complex scenes (stacks/piles of objects for example).

With the right parameters a good rigid body physics engine should be able to prevent noticeable interpenetration in most situations, though the performance cost may not be worth it. In these demos if you max out Position iterations, velocity iterations, and frequency you should see significantly less interpenetration.

As for continuous collision detection/sub-stepping, this is a very common feature to prevent fast moving objects from clipping into or tunneling through other objects. However resting/continuous contact cannot be handled by stepping to the next intersection time and so have to be handled differently. Also multiple simultaneous or near simultaneous collisions can grind things to a halt in degenerate cases (such as multiple stacked objects that are almost, but not quite in resting contact). This is why physics engines that support continuous collision usually let you set a maximum number of sub-steps.

dfbrown commented on Ugly Gerry – Font created from congressional districts   uglygerry.com/... · Posted by u/rgardaphe
Spivak · 6 years ago
One of the arguments in favor of the electoral college is that it boosts the voice of people who are in areas with lower population density. This is to ensure that minority interests are respected and taken into account by presidential hopefuls.

Without this protection the voices of people who live outside the 5 major metropolitan areas simply wouldn't matter and candidates would have no reason to listen to their issues and have no repercussions for hurting them to favor city-dwellers.

This would be bad. Very bad. A straight population vote ends up being a scheduling algorithm for issues where rural interests have unbounded wait time.

One could say that the solution of weighting rural votes higher is a clunky system but any replacement voting system needs to take this into account as those small towns are where almost all of our primary industry is.

dfbrown · 6 years ago
All but two state's electoral votes are decided by the result of the popular vote in that state, congressional districts have no effect on that.

Local and proportional representation is the main reason for having the house of representatives, while the reason for Gerrymandering is to disproportionately favor one party or another.

dfbrown commented on C++20 Ranges   ericniebler.com/2018/12/0... · Posted by u/ot
rudolph9 · 7 years ago
dfbrown · 7 years ago
No, ranges in C++ are analogous to the iterator trait in rust
dfbrown commented on Make photomosaics, GIFs, and murals from pictures in Python with ML/OpenCV   github.com/worldveil/phot... · Posted by u/muzakthings
dfbrown · 7 years ago
I'm not an expert in the topic, but my understanding is RGB is a poor color space for computing color difference. This could be why your mosaics end up so washed out. [1] suggests using a CIELAB color space [2].

Edit: Looking at the code more closely it looks like you were using Lab at one point but commented it out[3], so I'm guessing you're already aware of this.

1: https://stackoverflow.com/a/9019461/185171

2: https://en.wikipedia.org/wiki/CIELAB_color_space#CIELAB

3: https://github.com/worldveil/photomosaic/blob/bb720efda11383...

dfbrown commented on Timsort is a sorting algorithm that is efficient for real-world data   hackernoon.com/timsort-th... · Posted by u/signa11
Cynddl · 7 years ago
> Timsort is a sorting algorithm that is efficient for real-world data and not created in an academic laboratory.

It's always a bit sad to see academia as an ivory tower where researchers generate unusable knowledge. Academia is not only about finding theoretical pure solutions but often also about finding solutions to real-world problems. For instance, machine learning, logic design, networking algorithms, cryptography, all deeply depend on work done in academia (and not just “theoretical” work).

dfbrown · 7 years ago
In addition, in Tim's post on the python mailing list he says he developed the algorithm after reading through a number of papers on sorting[1]. So while the algorithm was developed with the goal of being practical, plenty of academic research was used to develop it.

[1]: https://mail.python.org/pipermail/python-dev/2002-July/02683...

dfbrown commented on Show HN: Minimal Fibers   github.com/basic-gongfu/c... · Posted by u/bgongfu
dfbrown · 8 years ago
Worth noting that ucontext is quite slow (at least on linux): https://www.boost.org/doc/libs/1_67_0/libs/context/doc/html/...
dfbrown commented on TinyVM – A small and easy to understand virtual machine in C   github.com/jakogut/tinyvm... · Posted by u/jxub
userbinator · 8 years ago
After seeing C4[1], everything else doesn't seem tiny at all... and maybe it's just me, but this is another one of those projects where I found the directory layout rather confusing, especially for something that claims to be "small and easy to understand." bin/ is empty, there's only a single nearly-empty file in src/, lib/ is also empty, include/tvm is two levels but one is empty, and all the interesting stuff actually appears to be in libtvm/ .

More importantly, even after going through all the files in libtvm/ , I still haven't managed to find the main instruction execution loop nor the decoding switch. Sorry, but I don't think "small and easy to understand" applies, and I've had experience with VMs and interpreters and the like for many years. Compare with this, for example:

https://github.com/tjmerritt/z80

A rule-of-thumb when investigating the source code of a project for the first time: if I have to go more than 2 directories deep to get to the "meat" of the code, my desire to explore further drops significantly.

[1] https://news.ycombinator.com/item?id=8558822

dfbrown · 8 years ago
C library public headers are commonly two levels deep to so that projects using them can add the "include" directory to their header search path and in their code have #include "<libname>/header.h". It helps avoid filename clashes.

u/dfbrown

KarmaCake day286August 9, 2012View Original