smilekzs (u/smilekzs)

smilekzs commented on Work disincentives hit the near-poor hardest (2022) niskanencenter.org/work-d... · Posted by u/folump

terminalshort · 2 months ago

To calculate the amount of your childcare benefit take the negative of the your adjusted gross income (box 26a), divide it by 10,000, and add 2. Then take the arctan of that result and multiply by 5,000. Add 2500π and write the result in box 46. You may round the value of π to 2 digits. If you are filing as head of household, divide the amount in box 46 by the definite integral from 0 to your adjusted gross income (box 26a) divided by 10,000 of sin^2(x)/(x^2 + 1) dx, and write that amount in box 48. If you are unable to find the function of the anti-derivative, IRS rules allow you to approximate with a Riemann sum using the midpoint rule and a rectangle width of 0.1.

smilekzs · 2 months ago

Or, as it has always been, piecewise linear approximate it.

smilekzs commented on Amazon launches Trainium3 techcrunch.com/2025/12/02... · Posted by u/thnaks

smilekzs · 2 months ago

Single-chip specs according to:

https://awsdocs-neuron.readthedocs-hosted.com/en/latest/abou...

https://awsdocs-neuron.readthedocs-hosted.com/en/latest/nki/...

Eight NeuronCore-v4 cores that collectively deliver:

    2,517 MXFP8/MXFP4 TFLOPS
    671 BF16/FP16/TF32 TFLOPS
    2,517 FP16/BF16/TF32 sparse TFLOPS
    183 FP32 TFLOPS

HBM: 144 GiB HBM @ 4.9 TB/sec (4 stacks)

SRAM: 32 MiB * 8 = 256 MiB (ignoring 2 MiB * 8 = 16 MiB of PSUM which is not really general-purpose nor DMA-able)

Interconnect: 2560 GB/s (I think bidirectional, i.e. Jensen Math™)

----

At 3nm process node the FLOP/s is _way_ lower than competition. Compare to B200 which does 2250 BF16, x2 FP8, x4 FP4. TPU7x does 2307 BF16, x2 FP8 (no native FP4). HBM also lags behind (vs ~192 GiB in 6 stacks for both TPU7x and B200).

The main redeeming qualities seem to be: software-managed SRAM size (double of TPU7x; GPUs have L2 so not directly comparable) and on-paper raw interconnect BW (double of TPU7x and more than B200).

smilekzs commented on TPUs vs. GPUs and why Google is positioned to win AI race in the long term uncoveralpha.com/p/the-ch... · Posted by u/vegasbrianc

bfrog · 3 months ago

We used to call these things DSPs

smilekzs · 3 months ago

This is quite accurate considering Google TPUs are VLIW machines.

smilekzs commented on TPUs vs. GPUs and why Google is positioned to win AI race in the long term uncoveralpha.com/p/the-ch... · Posted by u/vegasbrianc

cwzwarich · 3 months ago

Isn’t the 9000 TFLOP/s number Nvidia’s relatively useless sparse FLOP count that is 2x the actual dense FLOP count?

smilekzs · 3 months ago

Correct --- found a remark on Twitter calling this "Jenson Math".

Same logic when NVidia quote the "bidirectional bandwidth" of high speed interconnects to make the numbers look big, instead of the more common BW per direction, forcing everyone else to adopt the same metric in marketing materials.

smilekzs commented on Safe zero-copy operations in C# ssg.dev/safe-zero-copy-op... · Posted by u/sedatk

smilekzs · 4 months ago

Anecdote: 9 years ago I was at MSFT. Hands forced by long GC pauses, eventually many teams turned to hand-rolling their flavor of string_view in C#. It was literally xkcd.com/927 back then when you tried to interface with some other team's packages and each side has the same but different string_view classes. Glad to see that finally enjoying language and stdlib support.

smilekzs commented on The value of bringing a telephoto lens avidandrew.com/telephoto.... · Posted by u/freediver

PaulHoule · 5 months ago

Particularly if it this kind of of 50mm

https://findingrange.com/2022/01/14/7artisans-photoelectric-...

I had a long streak where I packed a DSLR with a 50mm everywhere I went and never took any pictures with it because I felt depressed. Switching to zoom lenses (particularly developing a protocol to get a distinct style of landscape protocols out of my kit lens) and getting into sports photography got me out of my funk, also that 7Artisan 50mm is so much more fun than any of the other 50's in my collection. Part of it is the challenge of manual focus, the other part is the extreme wide aperture which can take dreamy looking photos that are entirely different from what people have seen before.

smilekzs · 5 months ago

The image circle of this is APS-C sized => 1.5x crop factor => 75mm "full frame" equivalent.

I'd categorize this as more of a portrait lens (than "normal" as the 50mm moniker implies).

smilekzs commented on Tesla changes meaning of 'Full Self-Driving', gives up on promise of autonomy electrek.co/2025/09/05/te... · Posted by u/MilnerRoute

briandw · 5 months ago

Lidar is the first thing brought up in these discussions. Lidar isn’t that great of a sensor. It does one thing well and that’s measure distance. A visual sensor can be measured along the axis of spatial resolution (x,y,z) temporal resolution(fps) and dynamic range(bit depth). You could add things like light frequency and phase etc. Lidar is quite poor in all of these except the spatial z dimension, measuring distance as mentioned before. Compared to a cheep camera the fps is very low, the spatial resolution in x and y is pathetic 128. in the vertical, higher horizontal but its not mega pixels. Finally the dynamic range is 1 bit(something is there or not). Lidars use near infrared and are just as susceptible to problems with natural fog (not the theatrical fog like in that Roper video) and rain. Multiple cameras can do good enough depth estimation with modern neural networks. But cameras are vastly better at making sense of the world. You can’t read a sign with lidar.

smilekzs · 5 months ago

Lidars have been reporting per-point intensity values for quite a while. The dynamic range is definitely not 1 bit.

Many Lidar visualization software will happily pseudocolor the intensity channel for you. Even with a mechanically scanning 64-line Lidar you can often read a typical US speed limit sign at ~50 meter in this view.

smilekzs commented on Matmul on Blackwell: Part 2 – Using Hardware Features to Optimize Matmul modular.com/blog/matrix-m... · Posted by u/robertvc

totalperspectiv · 5 months ago

I don’t follow your logic. Mojo can target multiple gpu vendors. What is the Modular specific lock in?

smilekzs · 5 months ago

Not OP but I think this could be an instance of leaky abstraction at work. Most of the time you hand-write an accelerator kernel hoping to optimize for runtime performance. If the abstraction/compiler does not fully insulate you from micro-architectural details affecting performance in non-trivial ways (e.g. memory bank conflict as mentioned in the article) then you end up still having per-vendor implementations, or compile-time if-else blocks all over the place. This is less than ideal, but still arguably better than working with separate vendor APIs, or worse, completely separate toolchains.

smilekzs commented on Selfish reasons for building accessible UIs nolanlawson.com/2025/06/1... · Posted by u/feross

smilekzs · 8 months ago

> The active class is clearly redundant here. If you want to style based on the .active selector, you could just as easily style with [aria-selected="true"] instead.

I vaguely remember (from 10+ years ago) that class selectors are much more performant than property selectors?

smilekzs commented on Car companies are in a billion-dollar software war insideevs.com/features/75... · Posted by u/rntn

tacker2000 · 9 months ago

Software defined vehicle? Never heard of this term. More marketing buzzword BS.

Yes, Tesla has one of the best user interfaces in a car, and has set the bar high. But just because they have OTA updates it's now called a "Software Defined Vehicle"?

smilekzs · 9 months ago

From first principles I think the concept can make sense. From car-specific function-specific ECUs, to platform-shared (but still function-specific) ECUs, then to Zonal architecture and domain controllers. The goals: consolidate and generalize HW across the lineup moving model-specific bits to FW/SW/Config (amortizes the development cost and simplifies certification), and also simplify wiring (saves you precious copper wires which are costly, messy, and heavy) because you can pretty much just plug every miscellaneous sensor or actuator to its nearest "anchor point" without worrying (too much) about arbitrary ECU limitations.

See Rivian's intro on their ECU design and Zonal architecture: https://youtu.be/6ZBko4TvfJY?t=137&si=-SKL_iFqZFnHE8nQ

This might sound like purely implementation detail, but having the (non-safety-critical) "business logic" of a car as software gives the manufacturer flexibility to late-bind behavior as new use cases / demands inevitably get discovered.

Something can simultaneously be a good idea, buzzword'd by marketing, and/or deviate from the original intentions.