Yet another Hacker News

Can a Linear Program Do Weight-Space Programming?

149 points emschwartz 4 hours ago 25 comments

dansitu 3 hours ago | parent

Nice analysis. The simplicity of this indicates that it should be happening during training via regularization.

FrustratedMonky 3 hours ago | parent

Does this describe a very powerful LLM, like Astra, editing smaller models?

Could Astra edit itself?

kragen 3 hours ago | parent

No, it describes a linear optimization algorithm from the 01940s editing a Qwen model with billions of parameters.

FrustratedMonky 3 hours ago | parent

"In another experiment, they asked Astra to make Qwen3.5-0.8B better at math by editing its weights"

nullc 3 hours ago | parent

Which it did by doing an inefficient version of the aforementioned 1940s algorithm.

Essentially modern LLMs are able to do normal AI engineering tasks, like running optimization algorithms over weights. The media has been inaccurately describing this as if the AI had some special insight into the weights, when it reality it just performed the tasks a human engineer might do.

yorwba 3 hours ago | parent

Right, humans don't need some special insight into weights either, since it's just a bunch of numbers that you can analyze like any other table with numbers. However, if you dump them on someone like in this prompt: https://github.com/RikiyaT/lm_understand-logs/blob/main/exp1... they might complain about the formatting or ask whether they can use Excel instead of doing calculations by hand. (The experiment with Qwen3.5-0.8B didn't use the "dump weights into the context as numbers" approach.)

kragen 2 hours ago | parent

That's not what's being described here; that's described in another paper that this is a followup to.

rsfern 2 hours ago | parent

I don’t understand the negative reactions to your post, it’s a good insight.

Basically the weight edit approach is find a semantic direction for the undesirable behavior and steer away from it. With access to the weights I see no reason a model (even one as large as Astra) couldn’t apply that principle to itself. This probably includes at runtime if you wanted to give the model write access to itself

ultimatefan1 3 hours ago | parent

Good article! The initial headlines from a few days ago made it seem like frontier models were becoming able to read, understand, and manipulate weights directly. This seemed unlikely to me since they aren’t trained on weights, they’re trained on tokens and task completion (RL). This analysis makes me think a better description is that Astra did some interesting model training research that included running small experiments with altering weights and found a nice edit that fixes some problems. Cool, also cool that this analysis finds a faster approach. But a far cry from the headlines when the paper first came out.

FrustratedMonky 3 hours ago | parent

It seems a little like splitting hairs.

Astra didn't directly edit the weights, it came up with a method to edit the weigths?

So, it used another tool to edit the weights?

This kind of seems like saying, I don't directly edit the bits on my hard drive, thus i'm not really the one saving a file?

yunruse 2 hours ago | parent

It's easy to trace that a bit sets a character in a file with absolute certainty; weights are in a highly dimensional space however, so even if ⍺v is good for one test it could easily regress for another.

I suppose the argument is that "editing weights" seems to imply a complex awareness of what each weight means, which is material for AGI hype. Really it's just doing very broad statistics, which is of course interesting but hardly unexpected.

yatopifo 1 hour ago | parent

I look at it at a slightly different angle. AGI implies broad capabilities including self-improvement without using another AGI. Being able to perform a “surgical procedure” on weights is a clear step in that direction. Direct weight interpretation may work if small model weights are included as training tokens but i doubt it’s useful for self-editing. On the other hand, using simple tools to interpret and edit it’s own weights might work.

FrustratedMonky 36 minutes ago | parent

Yes, the arguments in this thread seem to be around interpreting the word "editing". Is something consciously "editing" by tweaking the correct neurons/weight. Or is it just some linear algebra.

Though, even on re-read, it sure seems like Astra was making some decisions, otherwise what is this saying, that Astra knew how to download some linear algebra tools?

Filligree 1 hour ago | parent

The weights ended up edited. It does feel a bit like the long of reasoning that claims LLMs don’t really think, while they’re doing novel mathematical research.

wasabi991011 15 minutes ago | parent

I think the distinction is relevant even if the exact line is blurred. Two extremes:

It would be extremely surprising for a model to be able to ingest all model weights in a prompt and output better model weights, with no tool calls. While certainly possible for small simple models (eg a 4-parameter perception), at scale this becomes difficult in terms of near-perfect recall at huge context size and requires a superhuman intuitive understanding of linear algebra.

On the other hand, it is extremely unsurprising that a model can edit weights when having access to unrestricted tools, time, and resources (including non-public resources that the AI labs have). The methodology is fairly simple: just train the model more on whatever better non-public datasets. Hell, just benchmaxx the smaller model, that would be "a method to edit the weights" that achieves the necessary results.

I think everyone would agree that these two scenarios are very different. Where the actual Astra weight-space programming result falls on this spectrum is debatable.

nullc 3 hours ago | parent

annnd we can just 'reinvent'(*) the same techniques used to uncensor models for some time.. one step at a time.

(*) scarequotes because the LLMs that suggested these approaches have presumably been exposed to the refusal direction suppression work

anon291 1 hour ago | parent

You cannot really train on second-order effects, and if you could, then you wouldn't be able to escape third-order effects, ad infinitum.

jsw97 2 hours ago | parent

Maybe this is what the author is getting at, but if LP solvers are useful tools for editing weights, then Astra access to this methodology might make it more effective at weight editing.

The interpretation here is not so much that an LP can do Astra's work -- after all the Astra prompt was "improve Qwen's math by changing weights" or similar. Instead, it's that with some guidance (eliminate this behavior, preserve that behavior, as expressed through linear constraints) the solver is much more efficient than Astra's trial and error. So essentially the solver would be a way of cutting through all the time consuming stuff and expressing Astra's intent more immediately. And then presumably Astra could iterate on that to a better solution.

The use of an LP solver here is a really cool insight.

boxfire 12 minutes ago | parent

I’d really love to see an LLM that can do augmented thinking without being prompted to. External LP or SAT solvers or CLP unifiers or provers, not as “tool calls” structured as JSON structured output but rather in the embedding space in shorthand representations native to token expression that the inference engine dispatches uniquely.

It’s possible to make a differential work through those too in a useful sense, which allows their integration to be at a more fundamental level than post training bolt-on, but that’s not friendly to mass gpu parallel training without some serious work.

A conversation with an engine that thinks with the power of constraint solvers “baked in” instead of having to be brow beaten into approximate truth and iterated millions of times to care to even try to follow through to it. Wow that’s almost all I ever wanted. Here’s my word problem, go do the actual reasoning, hand waive until you’ve got enough expressive power to make an answer but if you can see a formal structure state it natively and let an actual solver spit out the (unification/feasible space/etc) back into token space that the llm picks back up on.

rbnafo 2 hours ago | parent

Very interesting analysis. It would be great to see the LP comeback and optimize. I always have the impression that we have settled to suboptimal solutions in many areas just because we have become too attached to LLMs, wary of numerical analysis.

esafak 2 hours ago | parent

Reminds me of the time someone showed you could get as good results from linear regression as the more expensive SVM, like this: https://proceedings.neurips.cc/paper/2021/file/26d4b4313a7e5...

ricksunny 53 minutes ago | parent

So we are talking about linear programming a la operations research / industrial research / e g simplex? That would be wild if 1940s-50s OR fills in a key step to p̶o̶s̶s̶i̶b̶l̶y̶ ̶e̶n̶d̶ ̶o̶f̶ ̶t̶h̶e̶ ̶w̶o̶r̶l̶d̶ RSI (if that’s the subtext on the table here). Because then I guess if the world does end, it’s just one more world-ending technology we can blame on the 1940s-50s.

daemonk 9 minutes ago | parent

What exactly is the difference between weight-space programming and something like back propagation? I guess AI can reason deeper about the weights somehow and take into account more parameters than a simple feedback from back propagation?