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dgacmu

7,871 karma · joined February 12, 2013

CTO and founder, Enriched Ag. Computer science professor at Carnegie Mellon University. Ex- university of Utah, MIT, Google Brain.

http://www.cs.cmu.edu/~dga/

Of the firm belief that distributed systems is the coolest area ever, followed by computer science in general. Yes, I'm a bit biased.

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dgacmu··on Livenerf: Has Opus 5.5 been nerfed yet?
Except for that one year when they completely swapped the meaning of the Cumulus line, which I think was 2008 with the cumulus 9 to 10 transition. It went from a neutral shoe that was good for people with high arches to more of a stiff stability shoe. The complainers aren't _always_ crazy. :-) (That doesn't mean the cumulus 10 was worse, of course, it just was a more substantial change that affected the type of runner the shoe was designed for.)

Wow the old grumpiness that lingers in my head from losing my favorite shoe. Who knew? Now I'm old and heavier and run in the Nimbus and am happy again. But you're right, of course, that most of the model changes are just fine and people like to complain.

dgacmu··on Ten lines of code that changed my world
Most definitely the juvenile phrases.

I think my second BASIC program was the "guess a number" one -- that seemed really popular in intro basic programming things in the 80s also since it showed keyboard input and conditionals and was, uh, fun-adjacent.

dgacmu··on We're gonna need a lot more mathematicians
We've been those ants for a million years, and only in the last 100 did we start to wrap our heads around quantum physics. We are the purpose behind creating LLMs. There's plenty in the universe we don't understand, and it's very human to keep striving to do so.

If you believe that math is discovering, it's natural to think that all of that AI math already exists and is just waiting for us to find ways to discover and understand it.

Don't write us out quite yet. :)

dgacmu··on An airport cooled by natural ventilation
This is so humidity dependent though, so it's probably more useful to speak in terms of the heat index.

I didn't mind 100F too much when I lived in Salt Lake; it was hot but that's what drinking lots of water was for. In Pittsburgh, 93F and higher make me want to curl into a ball and hug an air conditioner. In the 90s the heat index reaches as high as 110 here. Ick.

dgacmu··on Initial DIY cleanroom experimentation
I don't know how general it is, but my dentist and kid's school kept the HEPA filters after covid. It's at least... a little better?

(Speaking personally, my home indoor air quality is now awesome and I love it. Wish it hadn't taken a pandemic to clue me in, though.)

dgacmu··on Creatine uptake enhances antitumor immunity
Your body can synthesize creatine, so it's not essential, but meat is a source of exogenous creatine and eating it results in higher stored creatine levels, which is slightly good for muscle power endurance in the ~5-15 second effort range. Supplementing produces slightly higher relative improvements in creatine levels in vegetarians and vegans than it does in people who eat meat.
dgacmu··on Tokens too cheap to meter
I've evaluated some of these and in almost all cases they failed to outperform Intel's ridiculously optimized CPU regex library, hyperscan.
dgacmu··on Launch HN: Coverage Cat (YC S22) – Umbrella insurance via your personal agent
seems reasonable to me! Thanks for responding.
dgacmu··on Launch HN: Coverage Cat (YC S22) – Umbrella insurance via your personal agent
Perhaps I'm not making myself clear: There might be reasons I _shouldn't_ be happy with it! Maybe I'm overpaying, maybe I'm missing out on subtleties of one insurer vs another, etc. And I mean, hello, I'm posting here, of _course_ i'd rather not talk to a salesperson on the phone.

Your post actually inspired me to go raise the amount of my coverage. I was paying attention. It triggered some thinking. It even triggered action. But maybe I wasn't paying attention to the part you wished I was.

dgacmu··on Launch HN: Coverage Cat (YC S22) – Umbrella insurance via your personal agent
I'm probably your target audience - I have umbrella insurance - but I just grabbed it through my existing GEICO/travelers insurance and it was basically painless. It isn't so expensive I felt compelled to shop massively for it and nothing I read above convinced me I'm wrong there?
dgacmu··on RSA-896
If you look at the numbers, he managed about 50% utilization of those 2048 GPUs over 10 days, so he was probably sneaking in factoring work between training runs.
dgacmu··on AI-generated posters don’t have to be horrible
One of my best memories from an art class in high school was that a student organization came into our class and asked if any of us would be willing to design a poster. I ended up designing and silk-screening their poster for them and it was a fantastic experience.

I can totally see how doing more than a couple would start to feel like work, but having one or two experiences like that was awesome.

dgacmu··on Small programming tricks
Also in academia but I'm old and my real work is done withy students. I'm coding by hand much less than I used to (boo) but solving more problems with code myself than I used to (yay). Having an llm do things turns out to be similar to having a student do them but with fast turnaround and it's fine to have them work on your home automation system. ;)
dgacmu··on Bad benchmarks and evals: Senior SWE-Bench, napkin math, and winter tires
I agree, I have the same problem, that's why I'm sticking with the crossclimates year round also -- we only drive about 5,000 miles per year, so my tires die from age well before they would wear out from mileage.

I assume we're both making approximately the same optimization but you're going for better snow & ice performance at the expense of some summer and wet stopping distance, and neither tradeoff seems obviously wrong depending on our driving situations.

dgacmu··on Bad benchmarks and evals: Senior SWE-Bench, napkin math, and winter tires
I dunno about this - I leave my crossclimate 2 aw's on year round and they're pretty fantastic in snow. We had a pretty good winter this year (44" from dec-feb) and they just worked. I didn't go meandering around any mountains on them, mind you, but they're so far ahead of most typical all-season tires it's almost not fair to compare. For -most- lazy people who don't want to swap tires or rims, they seem a better option than leaving true winter tires on year round. Obviously, there are exceptions depending on where you live.
dgacmu··on Base84 deserves a place in file names
Yeah, I'm sympathetic to their desire for compression and efficiency but base64URL is way more shell-friendly.

I quite like base58 for human-presented identifiers also. I tend to use it instead of hex for having ~8-16 character IDs of things.

dgacmu··on I Added a Non-Wi-Fi Mitsubishi AC to Home Assistant
But with most houses, the AC will cycle on and off throughout the day anyway - raising the temp while you're gone will often result in less cycling. Especially if you also increase the hysteresis range while out. So you get a triple efficiency win, from better AC efficiency, less AC motor wear, and less heat loss to the outside.
dgacmu··on LRU is harder to beat than the KV-cache papers suggest
"That's not a result, that's a broken harness, and it's worth publishing because I expect it to be common."

That's Claude. But I agree and am also glad the author, uh, clauded this up. :)

dgacmu··on Ask HN: Can we please limit the AI news flood?
On the brax thing - the "article" is a youtube video. There's a pretty reasonable amount of pushback here against video-only content where folks can't rip through quickly to figure out how relevant it is to them or if it's just a vapid ad.
dgacmu··on DeepSeek v4.1 Flash
Bandwidth is really cheap in bulk. You can get a 100 gigabit internet connection for about $10,000 a month. If you were to somehow keep that saturated 24/7, you'd move about 30 petabytes in a month, so your per gigabit cost is only $0.0003.

Realistically, if you had it 5% utilized, those million tokens would cost you about $0.0000062, which is pretty insignificant compared to what they charge you. (Assuming one byte per token, ignoring compression)

dgacmu··on I Connected My Withings Body+ to Home Assistant with an ESP32
esp32 bluetooth proxy: There's a standard esphome component that just turns any esp32 with appropriate h/w into a BTLE proxy: https://esphome.io/components/bluetooth_proxy/

I'm just using a cheap ESP-WROOM-32 but the recommended way to do it is with an wired ethernet-based ESP32 so you don't have interference with the wifi and btle. For a scale this works well enough. I haven't yet received the athom smart plug so I can't recommend it yet. Should be here in a week or so.

Once you've got the proxy you can just use the eufylife integration: https://www.home-assistant.io/integrations/eufylife_ble/

To setup the esphome bluetooth proxy you install esphome, and then create a yaml file that you'll use to configure the board, like this:

   esphome:
     name: bluetooth-proxy
   
   esp32:
     board: esp32dev
     framework:
       type: esp-idf
   
   # Enable logging
   logger:
   
   # Enable Home Assistant API
   api:
     encryption:
       key: "YOUR_KEY_HERE"
   
   # Enable OTA updates
   ota:
     - platform: esphome
   
   # WiFi configuration (matching the settings from your other devices)
   wifi:
     ssid: "YOUR_WIFI_SSID"
     password: "YOUR_WIFI_PASSWORD"
   
     # Enable fallback hotspot (captive portal) in case wifi connection fails
     ap:
       ssid: "Bluetooth Proxy Fallback"
       password: "proxyfallback"
   
   captive_portal:
   
   # Enable ESP32 BLE Tracker
   esp32_ble_tracker:
     scan_parameters:
       active: true
   
   # Enable Bluetooth Proxy
   bluetooth_proxy:
     active: true
Once that's done, plug in your board to your system and use esphome run bluetooth-proxy.yaml (you might have to find the device it's showing up as in tty.usbserial or whatever).
dgacmu··on I Connected My Withings Body+ to Home Assistant with an ESP32
If you have a eufy scale, you can do this with no LLM needed - just set up an esp32 Bluetooth proxy, add it to home assistant, and then use the EufyLife integration someone already made. I did this recently with my scale to avoid having to sync it to my phone, go to the cloud, fetch data from the cloud, etc., and it's working fantastically. I have a little Home Assistant integration that pokes scale updates to a Python script running locally that provides a UI I like.

Huge fan of running it this way.

(Yesterday I ordered a more commercial, polished-looking esp32 Bluetooth proxy integrated into a smart plug - athome brand - but it's the same functionality, just in a nicer package than having a USB thing dangling from my outlet)

dgacmu··on Research acceleration: The view inside OpenAI
Indeed, many programmers might pattern match to repetitive stress injury and think of their brushes with carpal tunnel syndrome. :)
dgacmu··on Artificial Analysis Intelligence Index v4.2
It does and that one also feels kind of saturated for measuring the most advanced models - opus, Gemini, astra, sol, fable, glm, kimi all scoring within statistical noise of each other. (74 +-3% down to 69% +-5% for kimi).

It's still providing strong discrimination between weaker models.

dgacmu··on Artificial Analysis Intelligence Index v4.2
I quite wish they'd move to terminal bench 4.0. 2.1 is saturated - there is no world in which Gemini 3.8 Flash is producing better code than Astra or Fable, as the 2.1 results might suggest. The 4.0 results differentiate these models much more effectively.

(2.1 is useful for knowing they can all one-shot straightforward scripts, of course.)

dgacmu··on IBM Bob
I think they started on a long slide starting in the late 90s when they tried to couple research more and more tightly to product deliverables, and then as they pivoted to being a services company, including selling off non-mainframe hardware to Lenovo, to coupling r&d to, uh, I guess services revenue, whatever that means. They had some research layoffs in 2008, at the same time that MSR and Google were really blossoming in research spend and perception, and I think they kind of got left behind.

I had a former student go there around 2008 and it seemed like the vibes were starting to sour around then. They maintained some awesome researchers in, e.g., databases, but I think the "make sure you are showing closely how your research directly contributes to services revenue" thing was strong by then and somewhat ruinous for how pleasant a work experience it was for many.

dgacmu··on IBM Bob
I laughed when I saw this; my 14yo looked over to see why I was laughing and asked "what's IBM?"

indeed, child, indeed.

dgacmu··on Scientists Find Worms in Almost Every Fish in a Tuna Haul – 96% Were Infected
It doesn't, really - this is a known hazard. You want fish that was flash-frozen very rapidly after harvesting. It's tastier and it kills (these types of) parasites. Which is basically what you're going to get at any decent sushi place.

Never too old to try something that is incredibly delicious. :-) My mom (born 1943) introduced me to sushi. Can't blame generation there.

dgacmu··on Evidence of Fraud in an Influential Study About Procrastination
It should - one of the papers that Data Colada reported on about Gino was co-authored with Dan Ariely: https://datacolada.org/98
dgacmu··on Benchmarking Pocket-Scale Inference
No - DRAM is made on a different process than compute. Apple uses dram made by the usual dram manufacturers.

The dram shortage is a combination of high demand + shifting manufacturing to HBM, which consumes more wafer capacity than DDR5

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