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phdelightful

441 karma · joined November 29, 2017

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phdelightful··on New York City should carefully measure a new tree
We should still have some public monuments even with the risk of them being vandalized.
phdelightful··on Mythic's analog compute-in-memory architecture
My understanding (perhaps outdated) is that manufacturing variability is a key challenge for analog computing. Digital designs are also fundamentally analogue under the hood, but if you only need to resolve a 0 or 1 you are much more tolerant of any source of noise. I wouldn't mind hearing even a little bit more from Mythic about how they make this work in practice.

A 2026 EE Times article [1] refers to "compensation" and "calibration" techniques.

[1] https://www.eetimes.com/mythic-rises-from-the-ashes-with-125...

phdelightful··on Being ambitious and being a dad
Earnestly: LLM hosting companies allow easy exchange of money for relatively nuanced language processing. Great power for filtering text anywhere you have the need.
phdelightful··on Amazonbot is finally respecting robots.txt
Thank you, I learned a few things!
phdelightful··on Amazonbot is finally respecting robots.txt
I didn't check thoroughly, but the first one I happened to grep out was not on that list:

"Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Amazonbot/0.1; +https://developer.amazon.com/support/amazonbot) Chrome/119.0.6045.214 Safari/537.36"

"x-forwarded-for":"44.210.204.255" "x-real-ip":"44.210.204.255"

This is a bit outside my area of expertise, so I don't know how reliable these x-forwarded-for and x-real-ip are.

phdelightful··on Amazonbot is finally respecting robots.txt
I just put Anubis in front of my self-hosted forge this morning because AmazonBot had helped itself to 750 GiB (!) of traffic to my public repos this month!

At least, it claimed to be AmazonBot…

phdelightful··on Meta is using the Linux scheduler designed for Valve's Steam Deck on its servers
Parent's article says

> Starting from version 6.6 of the Linux kernel, [CFS] was replaced by the EEVDF scheduler.[citation needed]

phdelightful··on Steam Machine
It’s <= a Radeon 7600 GPU (28 CUs RDNA3 vs 32), so I’m not sure I’d have advertised it as a 4k60 machine. Then again I’m not a marketer so what do I know. 4k60 is a flexible target with FSR I suppose.
phdelightful··on A visualization of the RGB space covered by named colors
What coordinate in the space is furthest from any named color? It looks like there are some relatively large voids in the blue/purple boundary area but it’s hard to say.
phdelightful··on AMD Radeon 8050S “Strix Halo” Linux Graphics Performance Review
I think I’d buy something with Strix Halo or Strix Point if there was official ROCm support. As of 6.4.1 from earlier this month there’s still not, as I understand it. I’d be delighted to be corrected on this matter.
phdelightful··on We're Raising Kids to Prefer AI over People–and No One's Noticing
The article goes on to say what the author thinks is bad about this:

> We’re not raising emotionally intelligent kids. We’re raising kids to navigate human unpredictability as if it’s a design flaw. Because when you grow up with a machine that always gets you, messy human behavior feels broken. We’re not preparing kids to handle people.

I don’t think there’s anything wrong with escaping into fantasy in the right time and place, but young kids (and even well-adjusted adults) can have problems self-moderating and letting fantasy substitute for engaging with reality.

phdelightful··on The Prospero Challenge
I compiled it for Ampere and counted 6834 actual F32 operations in the SASS after optimizations. I only counted FFMA, FADD, FMUL, FMNMX, and MUFU.RSQ after eyeballing the SASS code, so there might even be more. It's possible the FMNMX doesn't actually take a FLOP since you can do f32 max as an integer operation, and perhaps MUFU.RSQ doesn't either, but even if you only count FFMA, FADD, and FMUL there are still 3685 ops.

  nvcc -arch=sm_86 prospero.cu -o prospero
  cuobjdump -sass prospero | grep -E 'FFMA|FADD|FMUL|FMNMX|MUFU\.RSQ' | wc -l
phdelightful··on Show HN: A personal YouTube frontend based on yt-dlp
I basically have an even simpler version of something like this for my own personal use too. I found it pretty easy to write in Go and my area of expertise is decidedly not web frontend/backend. I’d recommend it as a fun little project if you’re looking for something to do.

For mine, I paste in a video or playlist URL and it downloads the video and creates a lower resolution transcoded version suitable for streaming to my phone. It also extracts an audio-only version in case that’s more appropriate.

phdelightful··on YouTube restores SineVibes channel after Peter Kirn & Ars Technica get involved
The Ars Technica article:

https://arstechnica.com/tech-policy/2025/02/youtube-briefly-...

(PS: Ars Technica is a bit sluggish for me this evening. Not sure why.)

phdelightful··on Show HN: We're building a desktop app for browser-based AI agents
Since you asked for “all the feedback,” there’s a typo on your landing page:

“The Meha API utilizes it's home-grown” -> “its”

Also, I got a relay access denied error when I tried to email you at info@meha.ai

phdelightful··on My failed attempt to shrink all NPM packages by 5%
My reading of OP is that it’s less about whether zopfli is technically the best way to achieve a 5% reduction in package size, and more about how that relatively simple proposal interacted with the NPM committee. Do you think something like this would fare better or differently for some reason?
phdelightful··on Unit Testing Numerical Routines
Yeah, we really just try to come up with very loose bounds since the analysis is hard. Even so, it does occasionally stop us from getting things way way wrong.
phdelightful··on Unit Testing Numerical Routines
I have worked on a performance-portable math library. We implement BLAS, sparse matrix operations, a variety of solvers, some ODE stuff, and various utilities for a variety of serial and parallel execution modes on x86, ARM, and the three major GPU vendors.

The simplest and highest-impact tests are all the edge cases - if an input matrix/vector/scalar is 0/1/-1/NaN, that usually tells you a lot about what the outputs should be.

It can be difficult to determine sensible numerical limit for error in the algorithms. The simplest example is a dot product - summing floats is not associative, so doing it in parallel is not bitwise the same as serial. For dot in particular it's relatively easy to come up with an error bound, but for anything more complicated it takes a particular expertise that is not always available. This has been a work in progress, and sometimes (usually) we just picked a magic tolerance out of thin air that seems to work.

Solvers are tested using analytical solutions and by inverting them, e.g. if we're solving Ax = y, for x, then Ax should come out "close" to the original y (see error tolerance discussion above).

One of the most surprising things to me is that the suite has identified many bugs in vendor math libraries (OpenBLAS, MKL, cuSparse, rocSparse, etc.) - a major component of what we do is wrap up these vendor libraries in a common interface so our users don't have to do any work when they switch supercomputers, so in practice we test them all pretty thoroughly as well. Maybe I can let OpenBLAS off the hook due to the wide variety of systems they support, but I expected the other vendors would do a better job since they're better-resourced.

For this reason we find regression tests to be useful as well.

phdelightful··on Llm.c – LLM training in simple, pure C/CUDA
Here’s a blog that breaks down how large different pieces of CUDA are:

https://carlpearson.net/post/20231023-cuda-releases/

phdelightful··on The Era of 1-bit LLMs: ternary parameters for cost-effective computing
It’s been a long time since I worked on FPGAs, but it sounds like FPGAs! What do you see as the main differences?
phdelightful··on Seaborn bug responsible for finding of declining disruptiveness in science
Your impression is correct. Peer review would never catch this. Peer review basically assumes the counter party is operating in good faith, and as a result a thorough peer review basically is the following:

* is the treatment of existing work semi-thorough (even experts don’t know everything) and fair?

* are the claims novel w.r.t the existing work? If not, provide a reference to someone who has already done it.

* can you understand the experiments?

* do the experiments and their results lead to the conclusions claimed as novel?

* does the writing inhibit understanding of the technical content?

No peer review I have ever seen or done would catch anything but the most egregious bug of this nature.

phdelightful··on AMD MI300 performance – Faster than H100, but how much?
DOE HPC people are not having this problem with AMD GPUs: here’s a paper that reports 1.36 TB/s on one GCD of an MI250x (theoretical is 1.6TB/s).

https://dl.acm.org/doi/pdf/10.1145/3624062.3624203

Table 6

phdelightful··on Implementing a GPU's programming model on a CPU
One of my colleague's Ph.D. thesis was on how to achieve high-performance CPU implementations for bulk-synchronous programming models ("GPU programming")

http://impact.crhc.illinois.edu/shared/Thesis/dissertation-h...

phdelightful··on Ask HN: What's the coolest physical thing you've made?
It’s far from what I do now, but as an undergrad I built an automatic guitar tuner. It had a PIC32 microcontroller that read the sound waves on GPIO pins and did some cross-correlations to figure out the frequency (sort of a poor man’s FFT, but faster since it was less general). It used an FPGA to drive a stepper motor to turn the guitar pins towards the correct frequency. Code was all C and Verilog.
phdelightful··on FedNow Is Live
In my line of US government coding (no relationship with this project), NDA is orthogonal to security. NDA is used to protect confidential vendor information. For example: that they have a contract with the government at all (in the case of a stealth startup), specific technical capabilities they don’t want broadcast to their competitors, the size of the contract vs. committed resources, etc
phdelightful··on Signal president says company will not comply with U.K. ‘mass surveillance’ law
Interpolate: to alter or corrupt by inserting foreign matter; but I have only seen it used this way for text
phdelightful··on Microsoft is bringing GPT-4 to US Government agencies
From my perspective, it seems two main things limit LLM adoption in my area of the Department of Energy. I'm not in management, so I don't have any particular insight in the procurement process.

1. Information sensitivity. Even ignoring classified information, there are quite a few things we can't even put into a Google search. It's definitely a no-go for this to end up in a training dataset.

2. "Hallucinations"

Making LLM available through some infrastructure that is already approved for sensitive information will definitely help with the first point, and allow us to experiment with more areas where it might be helpful. I presume this would come along with guarantees about the interactions not being used for training.

It might be even better if some company would sell an appliance we could install on-prem with similar non-training guarantees. Then we could leverage these new tools for very sensitive information, which could be a great help.

phdelightful··on Ask HN: Suing Facebook in small claims?
I achieved my quickest, simplest, most pleasant customer service interaction yet with an airline by writing a letter explaining what they did (with transaction IDs, confirmation numbers, etc), and what they should have done. The situation was not entirely simple, and I was not looking forward to explaining it verbally to a rep.

They sent me back a simple letter a couple weeks later saying they'd resolved the issue the way I requested and provided me the updated documentation.

I'll definitely consider this approach next time something like this happens.

phdelightful··on Tell HN: Crypto/web3 grifters are Now AI/ML grifters
> Framed another way, what you're describing here is that using ChatGPT is interesting enough to trigger engagement from social media users who are otherwise mostly inactive. If that is indeed the case, imo that is a pretty strong indicator of appeal to a wide audience.

I understood the comment to mean the posters are not posting about ChatGPT, but using ChatGPT to generate vapid (?, or inauthentic?) posts to farm engagement where there would otherwise be silence.

phdelightful··on Lottie 4.0 for iOS: new render engine with significant performance improvements
TFA says that their app loads faster for this reason with the new implementation.
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