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CJefferson

15,628 karma · joined June 18, 2010

Christopher Jefferson, St Andrews University, Scotland.

chris@bubblescope.net

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CJefferson··on Solving a corn puzzle with CP-SAT
I would be shocked if a good recursive backtracker could beat a good SAT solver for large problems. I mean, if you could solve SAT with recursive backtracking people would. That is the core of a SAT or CP solver, with the all the extra clever stuff.

I've spent significant chunks of my career help people throw away backtracking searchers people polished over years with a CP-SAT model I threw together in 30 minutes, often much to their upset.

You can for Sudoku often beat a CP-SAT solver, but that's because the problems are trivial and take milliseconds. If you look at more difficult Sudoku variants, or 16x16 grids, backtracking solvers start to fall behind.

CJefferson··on We're gonna need a lot more mathematicians
In the future I feel one parallel to this is my research area, SAT solving.

People used to solve logic problems by hand, verify logic. Now you pile it into a computer. The problem has been around for a while, no-one fully ‘understands’ the proof of the four colour theorem as a big chunk is computer proved.

We are now just changing (admittedly greatly) what we can put in a box marked ‘checked by computer.

CJefferson··on Asking authors about their own papers
Nope, I’ve tried this, it’s awful.

For a start LLMs love LLM generated text, so you are boosting papers people never had any input in.

Secondly, LLMs in my experience are good at small issues, but fail totally at the whole paper being obviously poorly constructed, or clearly fake.

CJefferson··on Apple M6 Pro Achieves the Highest Single-Core CPU Score in Geekbench 7
Something is going horribly wrong. I don't know what it is (without your code I don't know), have you profiled where it's going wrong? There's no way a game for 2004 would be that slow.

If you want help, I've done some similar work, you could pop it up on a github repo or something. What is the game?

CJefferson··on Microsoft exec called AI scraping 'the largest theft of labor in human history'
Anthropic getting angry other AIs are trained on their AIs output is, to me, one of the stupidest things I’ve read in a while.
CJefferson··on Microsoft exec called AI scraping 'the largest theft of labor in human history'
I mean, I don't seem to get to say, "Oh I want this but I can't buy it so I'll just steal it LOL", so why should AI companies?
CJefferson··on Microsoft exec called AI scraping 'the largest theft of labor in human history'
I'm 100% happy with either viewpoint.

1) AI companies all get sued out of existence.

2) AI companies can train networks with piracy, those networks don't fall under copyright, so give me a copy to do what I want with.

CJefferson··on Microsoft exec called AI scraping 'the largest theft of labor in human history'
No, but why should we accept they get away with it? Also Microsoft has definitely sued people for pirating windows and now collaborates with OpenAI and uses their ai trained on stolen materials.
CJefferson··on Microsoft exec called AI scraping 'the largest theft of labor in human history'
We don’t have to treat people reading books and companies stealing all human knowledge the same.

Also, companies spent a long time telling us downloading single songs via Napster was the worst thing ever, before torrenting every book in existence themselves. I don’t believe any of these companies have paid for all the books they have trained on.

CJefferson··on EU chief opens door for Canada to become 'associate member'
Well seeing as both Russia and the US want to mess with Canada and Europe, it’s doesn’t make that much difference, bot wise.
CJefferson··on OpenAI bots knew about the RubyGems caching vulnerability
I could make a non-deterministic chainsaw fairly easily. I’d also get sued into the ground if I sold it, and I wouldn’t be able to claim ‘Oh, it’s just an unavoidable part of progress’.
CJefferson··on Stop making swap partitions—use swap files instead
I mean, are you saying ‘but more RAM?’ because obviously yes that’s true but not a solution if you already own a laptop, and have you seen ram prices? Also swapping to a fast SSD isn’t like it used to be on spinning discs. I’ve been amazed how responsive Mac neo laptops are and they are swapping all the time.
CJefferson··on bzip3
Wow, that is widely disingenuous, I don't really think there is any excuse for that, I don't believe someone deep in compression algorithms wouldn't know they could adjust the block size, and 512GB is a huge block size for bzip3, as it needs to basically all be in memory so you can't pretend that's just 'the standard value'.
CJefferson··on Formalizing Fermat's Last Theorem
What’s interesting is it’s not obvious how this is leveraged to ‘cure disease’. But I’d love to know.the advantage of this is there is a clear measure of success. Here is a rule language. Prove this. You are done when your proof passes. You can sit quietly and spin for billions of tokens.

How does that work for drugs? We can’t let AIs make millions of test drugs and try them out on people.

CJefferson··on Claude Session URL appended to commit messages and PR descriptions by default
I don’t attach a raw dump of all the conversations I have with colleagues to my commit messages, and wouldn’t want to work in a place where I did.

Sometimes I tell Claude ‘don’t trust file X, it was written by a colleague who writes awful tests’. I don’t want that in my commit messages.

CJefferson··on Terminal-Bench-Science: Evaluating AI agents on scientific research workflows
I worry this doesn’t check correctness. I’ve been finding Claude is lately awful at folllowing instructions, I’ll ask it to implement the algorithm from a paper and it will do something simpler and slower and when challenged do it’s stupid apology thing. It can’t be trusted with anything I’d put in a paper, it lies too much. 4.6 couldn’t do as complex tasks, but it would do what was asked.
CJefferson··on Meta reaches $17B settlement over social media harms to children
This is completely different to my experience and my reading of the research. Please link me to any of this research you are talking about.
CJefferson··on Fable and the end of the free lunch
Much less than that. Anthropic won’t let its best model discuss my digestive system issues, or how to install apps on my own Peleton exercise bike.
CJefferson··on Fable and the end of the free lunch
I dislike all censorship, but US models are much more censored, I often find myself using Chinese models to get answers I want.

Now, of course I’d prefer no censoring, but I live in the world we live in.

I’m working in the assumption that (like today) there will always be somehow on openrouter, or similar, who will host a model I want to run.

CJefferson··on An update on leaving Gmail for Fastmail
My big problem with leaving Google is I’ve clicked on far too many ‘login with google’ boxes. In retrospect this was a mistake as it now ties my own domain to google basically forever, but lots of sites don’t even have the option to undo it.
CJefferson··on AI agent hacks gym to get its user a spot in pilates class
I'm a software developer. This is clearly bad, and we can decide what it should be called. It might not be 'hacking', but you are clearly abusing the computer to steal a space in a class you shouldn't have.
CJefferson··on AI agent hacks gym to get its user a spot in pilates class
My gym class operates on 'write on a piece of paper, cross off your name if you want to cancel'. I could cross someone else's name off and write mine in. They would have trouble figuring out it was me who did the malicious cross-off.

That wouldn't make it remotely acceptable of course.

CJefferson··on Study links GLP-1 drugs to bigger jump in women's employment than a degree
I find it amazing people don’t believe this. I lost about 50kg and people treated me better. They didn’t randomly shout ‘fat fuck’ in the street for a start.
CJefferson··on Zig's Incremental Compilation Internals
P.P.S.

Assuming you are replying to me, you seem to be projecting very powerfully. Rust isn't my favorite language, and I just asked about how much of your code was safe vs unsafe.

CJefferson··on Zig's Incremental Compilation Internals
Do you find most of your rust code is unsafe? Because I also find I do some unsafe stuff, because of the algorithms I work on I often end up with some unchecked array accesses and a couple of raw pointers into those arrays I pass around. But 98% of the code is safe and I find this makes it easier to reason about.
CJefferson··on Our position on open-weights models
Except it's 1,000x worse with the American models, because Trump might just decide that everyone in Europe get their access cut off, or gets a 5,000% tarriff. Or the companies just all agree to hike prices 10x one day. With open Chinese models, we can, in principle, run them ourselves.
CJefferson··on Our position on open-weights models
The problem is you can't ban open models.

All you can do is say that Americans have to pay whatever stupid prices OpenAI / anthropic / Google / Grok wants to charge you, while China uses, and attacks with, open models.

CJefferson··on Decathlon Germany adds Wero payment option to decathlon.de website
I'd much prefer NFC if I could see how much I was paying and had to always confirm it -- I understand this wouldn't have worked with physical cards but I wish it was an option on my phone.
CJefferson··on Decathlon Germany adds Wero payment option to decathlon.de website
This type of thing (scan QR code) is how basically all payments were done when I was recently in China, via wechat or alipay (either you show your QR code for big shops, or scan their QR code for small shops / vendors. They can just print them out if they want and hang a copy).

I found it superior to other systems I've used in basically every way. Particularly for small market stalls -- I scan their QR code, I enter how much I want to send them. They never get my details, I don't have to trust they didn't fat-finger the price. It also makes it amazingly easy to send money to friends, just scan their code and send them their share of dinner.

CJefferson··on US citizen charged after GrapheneOS phone wipes during airport search
This is where 'reasonable doubt' comes in from a jury. Would I believe that someone set up a 'wipe my phone' code, something that would be catastrophic, it was one digit different, and they accidentally typed it, or would I think they were trying to wipe their phone.

Honestly, given what I know here (a full case might be different), I would believe they did it on purpose.

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