Brandon Rohrer

Robots and data and robots learning from data.
https://brandonrohrer.org 
#Robots
#Robotics
 #ReinforcementLearning 
#MachineLearning
#DataScience

blog: https://brandonrohrer.org

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nprofile1qqsft6sgrf38emjyu5egykvxanrxyyuaq6xyhkktaqs23az9h8rvq6cprpmhxue69uhhyetvv9ujumt0d4hhxarj9ecxjmntrafrp4

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relay.momostr.pink

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npub1jh4qsxnz0nhyfefjsfvcdmxxvgfe6p5vf0dvh6pq4r6ytwwxcp4sl9eag0

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Last Notes

2026-09-28 23:40:52 GMT

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😢

2026-09-28 19:24:46 GMT

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and that you will get responses saying both

2026-09-28 19:24:21 GMT

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the fact that you can’t tell which way it goes is a strong signal that you’re doing something very right.

2026-09-19 01:34:53 GMT

RE: https://wandering.shop/@troublewithwords/117294766088155564
This was not what I was expecting and I’m so glad I watched it
#note1t4a…5sd7

2026-08-29 11:17:16 GMT

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my toxic trait is that I’m active on LinkedIn

2026-08-29 02:05:00 GMT

I wish there was a Virtuous Path I could follow:
an operating system,
a text editor,
a browser,
a social media,
a grocery store,
a government,
but they all seem to be run by people that practice some amount of fuckery, so I’m left looking for my least harmful options which involves making lot of unhappy calculations.
I can see the draw of religion. If someone could sell me a Virtuous Path I’d be into it.

2026-08-22 17:50:50 GMT

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heck yes you are!

2026-08-20 01:03:42 GMT

If you’re into such things, I’m going to be chatting with Josh Starmer and Luis Serrano (two of the best ML educators I know) in a YouTube livestream, answering viewer questions, at 11:00am EDT Thursday (tomorrow/today).
8am PDT, 3pm UTC, 5pm CEST
https://m.youtube.com/live/Yx-ZkLftybY

2026-08-14 02:12:28 GMT

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amazing. Thank you

2026-08-14 01:45:04 GMT

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so cool. If there happens to be a link you can point us to tomorrow, that would be awesome.

2026-08-07 11:17:04 GMT

The “why are we talking about dead cows?”-to-“I wish I didn’t know why we are talking about dead cows” pipeline

2026-07-21 13:07:34 GMT

Can I get some help spending money? I have a pot earmarked for technical books. Any recommendations on references for programming, databases, networking, algorithms, and all applications and adjacent topics? Bonus points if it’s something you wrote.
What has sparked joy for you?

2026-07-19 18:23:39 GMT

I love live music in theory, but is it always so loud?

2026-07-02 19:32:01 GMT

Well, great, apparently now I have to go invent something called Rohrer’s Razor
https://intheweights.com/p/vesselin-bontchev
https://cdn.masto.host/recsyssocial/media_attachments/files/116/852/045/762/143/885/original/636de88cce703580.jpeg

2026-06-25 10:05:10 GMT

RE: https://front-end.social/@stephaniewalter/116809572711174658
“The goal right now isn’t to optimize yourself into the shape the market demands. It’s to stay whole enough that when better conditions exist — and they will — you still have something left to bring.”
This piece may make you feel sad and angry and seen.
#note12uw…hn67

2026-06-21 11:17:07 GMT

This next round of Artisanal Language Model improvements are mostly focused on efficiency rather than dramatic algorithmic improvements.
https://brandonrohrer.org/alms_somm_sparse.html
I moved the Markov models from a dense representation, using arrays, to a sparse representation, using dictionaries. That cut the storage requirements down to a few percent of their original levels.

2026-06-10 15:27:00 GMT

the amount of delicious looseleaf black tea I drink would make me royalty in the 17th century

2026-06-06 13:37:30 GMT

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I ran into memory limitations quickly. Representing a 2nd order model with my 20,000-element dictionary required an 8 trillion-element array. It scales as O(n^3). I had to pare the dictionary down to a token alphabet of 1,000 to get it running. And predictably, with 1/20th the dictionary size performance went down, even with the higher order model.

2026-06-06 13:36:53 GMT

Old school language models, part 2: Second-order Markov Models
This is the next stop in my Artisanal Language Model development tour. If a first-order Markov model has a context length of 1, then a second-order has a context length of 2. Still miniscule compared to the thousands of modern LLMs, but it's instructive to see where the simple variants succeed and fail.
https://brandonrohrer.org/alms_somm.html
https://cdn.masto.host/recsyssocial/media_attachments/files/116/703/392/150/142/856/original/790586cb95491f69.png

2026-06-06 00:29:59 GMT

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sign me up for this cult! Take my earthly possessions!

2026-06-05 22:31:33 GMT

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but karl, karl surely there is one North Star metric we can use to evaluate every experience and use case that captures the nuance and complexity of oddball human behavior and expectations right? Right? Please say there is?

2026-05-27 19:59:11 GMT

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copy-pasting this for my next performance review

2026-05-19 18:26:17 GMT

RE: https://cosocial.ca/@mhoye/116602377072630702
Going back to sticky notes on my monitor is starting to look pretty good right about now
#note1zel…80ny

2026-05-12 13:57:51 GMT

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I mean, depending on the volume of traffic it might be fine. But some folks have seriously attempted to stream video directly from Codeberg repos. That’s a no-no.

2026-05-12 13:46:56 GMT

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I absolutely would! A few caveats
- Codeberg is a much smaller scale than the other players. Being a good citizen means not hosting huge binaries or using it as a content server that gets hit every time someone loads your blog. I have no compunctions against using GitHub for this.
- i think Codeberg doesn’t have things like GH Actions and other fancy CI automation pipelines. I don’t rely on those so it doesn’t hurt me.

2026-05-12 11:37:10 GMT

I host my blog repo on Codeberg with mirrors on GitHub and GitLab. It started as a fun exercise in overkill, but I’m feeling better about it by the day. It’s three times the hassle. But maybe going multi-infra is worth the robustness benefit when trusted institutions start failing.

2026-05-11 11:39:10 GMT

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kind of like how, once artificial diamond production got really good, the most valued diamonds are now the natural ones with small imperfections.

2026-04-20 11:36:32 GMT

Front end is my passion
https://cdn.masto.host/recsyssocial/media_attachments/files/116/436/827/434/342/557/original/5629e9c9f5ecfa36.jpeg

2026-04-16 11:24:33 GMT

The more I read about Python packaging the less I understand

2026-04-15 11:35:45 GMT

I can’t tell whether the Boston Globe wants me to feel happy or sad about this
https://cdn.masto.host/recsyssocial/media_attachments/files/116/408/512/790/831/346/original/c0395d4c3c7edbb9.jpeg

2026-04-14 20:28:51 GMT

This from @npub1fzn…nnyk came across my RSS feed. Chef’s kiss worthy, as always.
https://vickiboykis.com/2026/04/13/mechanical-sympathy/

2026-04-13 14:01:55 GMT

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Menopause Manifesto by Dr Jen Gunter is excellent

2026-04-10 11:34:47 GMT

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Banksy-level art here. Thank you for this

2026-04-09 01:22:44 GMT

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hooooly crap what a ride. I always thought espionage movies were exaggerating. I never suspected they were underselling reality.

2026-04-01 22:32:48 GMT

You want to see a rocket go to the fucking moon? Happening in two minutes!!!
https://www.youtube.com/live/Tf_UjBMIzNo?si=RImwNgSRjgIPm63l

2026-03-25 13:43:31 GMT

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that’s a hell of a hook. Would watch.

2026-03-14 15:03:26 GMT

Any sufficiently detailed sourdough recipe is in distinguishable from erotica

2026-03-03 13:38:08 GMT

Signature move of a good Baltic rye
https://cdn.masto.host/recsyssocial/media_attachments/files/116/165/514/613/170/812/original/722d11f59a5777fc.jpeg

2026-03-02 01:46:14 GMT

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thank you!

2026-02-10 00:17:58 GMT

I’ve played embarrassingly few computer games (and most of those in a quarter arcade) but the Fallout tv show makes me want to give it a go

2026-02-06 02:08:42 GMT

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🤦
I think it's fixed now

2026-02-06 01:25:47 GMT

There are one hard problems in computer science

2026-02-03 01:37:39 GMT

I'm glad to see people are enjoying my janky little drawing app.
(It's me. I'm people.)
https://graffitiwall.nexus
https://cdn.masto.host/recsyssocial/media_attachments/files/116/004/129/830/070/654/original/dc1bf405ce06200f.png

2026-01-29 12:17:15 GMT

The Boss, indeed
https://youtu.be/wWKSoxG1K7w

2026-01-28 23:50:52 GMT

I wonder which is more damaging for you—everyone telling you you’re inadequate or everyone telling you you’re amazing

2026-01-27 12:18:43 GMT

I made a silly little thing. In case you need to microdose some silly today.
https://graffitiwall.nexus
https://cdn.masto.host/recsyssocial/media_attachments/files/115/967/014/922/201/040/original/618d8983451adf3f.png

2026-01-25 03:27:30 GMT

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very good looking site! Instant rss sub

2026-01-24 14:51:34 GMT

🎶🎵🎶
A scream
is a wish
your heart makes
🎶🎵🎶

2026-01-23 23:24:27 GMT

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oh someone beat me to the joke!

2026-01-23 15:16:38 GMT

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dark coffee today. With you on this. 💙💜💚🩵🩷🩶

2026-01-23 15:13:59 GMT

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text supplied by my wife, sentiment supplied by my Shih Tzu

2026-01-23 14:35:59 GMT

https://cdn.masto.host/recsyssocial/media_attachments/files/115/944/912/008/682/105/original/ede833b28a4fcd68.jpeg

2026-01-22 16:14:50 GMT

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you must be so productive! #lifehacks

2026-01-21 13:51:49 GMT

Solid group therapy session for anyone in tech
https://www.anildash.com/2026/01/05/a-tech-career-in-2026/

2026-01-21 11:33:36 GMT

https://cdn.masto.host/recsyssocial/media_attachments/files/115/932/870/203/753/483/original/8e42fa4e5cce2cdb.jpeg

2026-01-21 00:51:58 GMT

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that is three Shih tzus of hair

2026-01-19 12:52:00 GMT

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I feel like the name “greedy algorithm” is kind of judgy

2026-01-19 12:43:14 GMT

The cool thing about starting with the lowest hanging fruit is that there will always be another piece of lowest hanging fruit.

2026-01-18 23:01:35 GMT

The answer to almost every programming question is “it depends” so it is remarkable that the answer to “when should I do this refactor?” is “right now”. I’ve never regretted it.

2026-01-16 23:45:17 GMT

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pro tip: If you image search "the sweet boutique fuck ice cookies" it pulls up something very different

2026-01-16 23:01:09 GMT

Mass. bakeries do not mess around.
https://cdn.masto.host/recsyssocial/media_attachments/files/115/907/262/182/149/101/original/e1bbff718aa587e2.png

2026-01-15 15:32:42 GMT

The autistic urge to write a Risks section that is four times longer than the rest of the document combined

2026-01-13 21:38:30 GMT

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at least they are consistent 🙄

2026-01-13 11:48:17 GMT

“but you haven’t tried the *latest * models”
[@iris_meredith](https://mastodon.social/@iris_meredith ) did, so you don’t have to. An open eyed snapshot of 2026 coding assistants. https://mastodon.social/@iris_meredith/115887026554644125

2026-01-03 01:04:07 GMT

If the tone of Technology Review is anything to go by, patience of the mainstream with LLM hype is wearing thin.

2026-01-02 20:05:04 GMT

RE: https://hci.social/@mdekstrand/115826575230913077
"Some of the best websites in the world are just HTML, and they belong to their authors. ... Don’t get caught up in tooling and frameworks, just write HTML and get something online. If you’re an engineer, delight that you’re not beholden to the same standards of quality and rigorous testing that you are at work — draft some ideas, hit the h1 to p tag combo, and publish."
#note169e…cgud

2026-01-01 15:30:05 GMT

happy new year
https://cdn.masto.host/recsyssocial/media_attachments/files/115/820/553/872/330/683/original/3fca8c4c6b6d4b27.jpeg

2025-12-31 22:53:46 GMT

RE: https://hachyderm.io/@nedbat/115815743499718930
OF COURSE I clicked. Now all I can do is repeat [@nedbat](https://hachyderm.io/@nedbat ) 's warning. Save yourselves. It's too late for me.

2025-12-31 22:15:47 GMT

I know today’s date but could not with confidence tell you the day of the week

2025-12-31 18:02:38 GMT

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genuine gratitude for the eye rolling/day brightening

2025-12-31 17:58:03 GMT

PAVEL
@npub1yyd…d3ge https://mastodon.social/@PavelASamsonov/115815180936717189

2025-12-31 03:01:29 GMT

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But instead I nerdsniped myself into writing an arbitrary precision addition function
https://codeberg.org/brohrer/graffitiwall-server/src/branch/main/arithmetic.py
Because it was focused on such a tiny slice of functionality with a particular use case, I was able to craft it to be simple and to give exactly the behavior I want.
If you discover any breaking cases in the Adder app please let me know. I've been having a really good time putting it together and now feel an unreasonable amount of pride in it.

2025-12-31 03:00:30 GMT

It is surprisingly hard to get computers to do addition with decimals the way a third-grader can.
adding floats gives things like
0.1 + 0.2 = 0.30000000000000004
https://graffitiwall.nexus/graffiti_adder.html
The mpmath library in Python is capable of arbitrary precision, but still gives things like
-1.2 + 1.21 = 0.009999999999...
https://mpmath.org
The answer I was looking for was Python's decimal library. It gives
0.1 + 0.2 = 0.3
and
-1.2 + 1.21 = 0.01
https://docs.python.org/3/library/decimal.html
https://cdn.masto.host/recsyssocial/media_attachments/files/115/811/941/266/725/311/original/e341c7ad07b83a88.png

2025-12-29 01:47:52 GMT

4 STARS from @npub1503…fme5 ⭐️⭐️⭐️⭐️
https://weatherishappening.network/@WEATHERISHAPPENING/115800132926368560

2025-12-28 20:03:07 GMT

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UNGOVERNABLE

2025-12-28 03:00:38 GMT

My Magnificent Adding Machine app has gotten a glow up.
https://graffitiwall.nexus
- no floating point weirdness
- a bit of amateur web design
- timing info
- a beefy database behind it
I won't say unbreakable, but harder to accidentally break.
https://cdn.masto.host/recsyssocial/media_attachments/files/115/794/938/986/638/436/original/5499e6a613316230.png

2025-12-27 14:23:19 GMT

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this makes my LoTR nerd heart sing

2025-12-27 14:12:08 GMT

This is doubly funny if you watch her character in A Man on the Inside
https://mastodon.gamedev.place/@mtothevizzah/115788551133863383

2025-12-25 23:55:52 GMT

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not all heroes…

2025-12-23 18:39:25 GMT

I’ve been intimidated by Postgres for a long time, but now that I’ve gone and got it working I feel kind of silly. It is a wildly powerful tool, so I expected to have a painful installation with building from source and modifying environment variables, but it turns out Postgres is built to be put to use quickly.
https://brandonrohrer.com/postgres_intro.html

2025-12-22 22:18:56 GMT

A long time SQLite user, I’m using my own Postgres server for the first time and having a real “I know kung fu” moment

2025-12-22 16:27:21 GMT

When I meet someone I've stopped asking myself whether they're fucked up. Instead I ask myself what flavor of fucked up they are. If I can't tell it means I don't know enough about them yet. The fuckedupedness is a foregone conclusion.

2025-12-22 12:19:29 GMT

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I’m expecting these to eventually become “promoted”, “please please” and “watch these dammit”

2025-12-21 20:23:42 GMT

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stunning. Someone pulls a strong line.

2025-12-21 20:14:45 GMT

me: no need for code hygiene or documentation. I’m the only one who’s ever going to see it.
3- days-from-now-me: what asshole wrote this

2025-12-20 15:08:26 GMT

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I love how installing and spinning up a postgres server in Linux is a one-liner

2025-12-20 15:07:38 GMT

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I resonate with this approach. It is definitely on my short list.

2025-12-20 13:06:13 GMT

seeking database opinions
It's a wild swing, but does anyone have experience with a database that
1. handles concurrency well
2. is a columnar store
3. is open source
Here is list of 2 with 3, but doesn't help with 1.
https://en.wikipedia.org/w/index.php?title=List_of_column-oriented_DBMSes&section=1#Free_and_open-source_software_(FOSS)

2025-12-19 18:00:22 GMT

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But don’t lose your head. You wouldn’t want to end up like Windows. Have some self respect.

2025-12-19 17:18:25 GMT

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be ungovernable
#govpunk

2025-12-19 15:07:57 GMT

Live with the confidence of someone who starts their version numbering at 1.0

2025-12-19 01:23:51 GMT

Apple TV just recommended me an M Night Shamalan and I'm trying not to feel insulted

2025-12-16 13:53:16 GMT

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I think I fixed it.
https://graffitiwall.nexus
https://cdn.masto.host/recsyssocial/media_attachments/files/115/729/574/155/603/761/original/240de219dbbc920c.png

2025-12-16 13:51:48 GMT

My gratitude to @npub1vgc…6zv2 for this cool html injection attack and reminding me about the importance of client-side validation.
https://kolektiva.social/@lumecolca/115727469759214470

2025-12-16 13:49:25 GMT

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OK this is very cool and a very good client-side validation cautionary tale.
I think I patched this particular hole

2025-12-16 05:04:50 GMT

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what am I even looking at here? I feel like there is secret knowledge being bandied about

2025-12-16 05:01:20 GMT

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I don’t understand this. But I’m going to.
https://cdn.masto.host/recsyssocial/media_attachments/files/115/727/484/001/406/992/original/92601bda78a2d930.jpeg

2025-12-15 15:58:09 GMT

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Tilly Seuss

2025-12-15 14:15:31 GMT

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My clickbait LinkedIn post:
It gives narrow-domain performance at super-human levels and exceeds benchmarks on this task for Gemini, GPT, Claude, and DeepSeek, far faster and at practically no cost.

2025-12-15 06:27:35 GMT

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what are you talking about that’s totally how math works