HN.zip

Rio de Janeiro's "homegrown" LLM appears to be a merge of an existing model

92 points by unrvl22 - 53 comments
zinodaur [3 hidden]5 mins ago
Oh no, someone is profiting off of their work without proper attribution!?!?
Aurornis [3 hidden]5 mins ago
This is an open weights model based on other open weights models.

The dispute is that they released it with claims about having done some post training that improved the outputs. It was discovered that the model was not post trained like they claimed.

The HF page now says it’s a merge of models, which wasn’t there before. They’re trying to claim they accidentally uploaded the wrong model to HF and that they’ll upload the real one soon.

Basically, they thought they could splice two open weights models together and claim their team had accomplished some amazing post training, but they weren’t smart enough to realize that other researchers would discover that there wasn’t any post training.

moritzwarhier [3 hidden]5 mins ago
Thanks for the factual clarification. This is so important when everyone already has their trigger finger on politics. Not meaning that politics are irrelevant here, see sister comment by jobim.

But it's impossible to form a nuanced opinion when political association has a higher priority than the facts; which, again, don't look flattering for the implementers.

carlosjobim [3 hidden]5 mins ago
This is a pure scam on tax payer money. But what else would be expected?
jrm4 [3 hidden]5 mins ago
Unlike the big companies who do this, which often are merely impure scams on tax payer money a little more downstream.
carlosjobim [3 hidden]5 mins ago
Great, now we're defending embezzlement and fraud with public funds on HN, because we really really hate big business.

A child caught doing something bad will cry "but my friends also did it!", is that the level of reasoning hackers want to be at?

blanched [3 hidden]5 mins ago
That seems like a bad faith read to me. Nobody is defending it, just pointing out the irony / hypocrisy. Two things can be bad, and they can be related.
jrm4 [3 hidden]5 mins ago
What part of that said "defense?"

They can both be bad.

internet2000 [3 hidden]5 mins ago
Attribution isn't the relevant part. Lying about your lab's capabilities is.
Planktonne [3 hidden]5 mins ago
That's also something all the AI companies have been doing.
dofm [3 hidden]5 mins ago
Lying about model capability is right now the lingua franca of the cloud AI business model, almost; they yes-and each other's lies because they are in a position of needing to generate interest, including going as far as needing to trigger regulatory capture.

(It's not news to anyone who has worked in sales-led businesses that salespeople are prone to believing the claims of other salespeople, I guess).

outside2344 [3 hidden]5 mins ago
But the whole game is lying and stealing isn't it?
adrian_b [3 hidden]5 mins ago
I do not see anyone lying.

The model card says:

> Post-trained from Qwen 3.5 397B

The model card also says that they use an inference framework based on "SwiReasoning: Switch-Thinking in Latent and Explicit for Pareto-Superior Reasoning LLMs" by Shi et al.:

https://arxiv.org/abs/2510.05069

So the sources seem properly attributed.

They only claim that what they did to "Qwen 3.5 397B" has improved the LLM, including, as expected, with "strong performance in Portuguese".

petu [3 hidden]5 mins ago
That's attribution to Qwen team.

There (is/was) no attribution to Nex team (they've released a model based on Qwen 3.5 397B as well).

As per OP link Nex claims that what Rio team released (so far) is just linear interpolation of weights between Nex and OG Qwen model. With no attribution to Nex and zero signs of Rio doing any training of their own.

00index [3 hidden]5 mins ago
Are you talking about the credit that was just updated an hour ago? lol
functionmouse [3 hidden]5 mins ago
leopards ate my face
woadwarrior01 [3 hidden]5 mins ago
Are you new to the latest AI hype cycle? /s
bachmeier [3 hidden]5 mins ago
"Their work"? First you had the original content creators that did 99.99% of the work. Then you had the US companies bundle it up into a frontier LLM. Then "they" did the "work" of using the US model as a foundation for their own. So in the sense of doing 0.00001% of the actual work that went into their product, sure.

I'd say it's more like someone forking a Linux distro, adding a few themes and fonts, and then complaining when someone else forks their distro and adds another theme.

JoshStrobl [3 hidden]5 mins ago
That joke really went over your head, huh...
dghlsakjg [3 hidden]5 mins ago
That’s the joke.
bwilliams18 [3 hidden]5 mins ago
That was the joke of the parent comment.
harikb [3 hidden]5 mins ago
It is only a problem if you claim it to be an independently developed OS with no attribution to base
idiotsecant [3 hidden]5 mins ago
Oof this is delete your post level I think. Sorry bud, I been there.
unrvl22 [3 hidden]5 mins ago
The municipality of Rio de Janeiro (via its IT company IplanRIO) released Rio-3.5-Open-397B, presented as a homegrown Qwen3.5 fine-tune that beats comparable open models on benchmarks. The linked issue argues it's actually a weighted merge of ~60% Nex-N2 Pro + ~40% Qwen3.5-397B-A17B - Nex-N2 having been released about a week earlier.
DonsDiscountGas [3 hidden]5 mins ago
I didn't know model merging like that was possible. (Obviously possible from a pure software standpoint but I'm surprised it's effective)
Lucasoato [3 hidden]5 mins ago
So the problem isn’t in the missing attribution to Qwen, but with the fact that they didn’t mention Nex-N2 Pro right?
Aurornis [3 hidden]5 mins ago
The problem is that they claimed to have made a big achievement with their home grown post training, and they expected to receive a lot of praise for it.

Then researchers looked at the weights and there is no post training at all.

They are now attributing both models they merged, but their excuse for the lack of post training is to claim they accidentally uploaded the wrong files.

fkozlowski [3 hidden]5 mins ago
I'm honestly surprised that they even had the inclination to attempt creating a model. I guess it's bullish that a municipal IT department had the guts to try this?
jrm4 [3 hidden]5 mins ago
“Well, Steve (Jobs), I think it’s more like we both had this rich neighbor named Xerox, and I broke into his house to steal the TV set, but I found out that you had already stolen it.”

-- Bill Gates

wunderlotus [3 hidden]5 mins ago
lmao i really hope this is a real quote cuz it’s a banger
AlienRobot [3 hidden]5 mins ago
The model's webpage at https://huggingface.co/prefeitura-rio/Rio-3.5-Open-397B says it's a merge now. It previously didn't contain this paragraph:

>The model is built via a merge of https://huggingface.co/nex-agi/Nex-N2-Pro and https://huggingface.co/Qwen/Qwen3.5-397B-A17B, proceeded by On-Policy Distillation from a stronger model. We detected an incorrect upload in the previous version, where the base merged version was upload instead of the final distilled model. We are sorry for the confusion and apologize profusely.

Incidentally are people using Github issues as blogs now?

ekjhgkejhgk [3 hidden]5 mins ago
One funny thing about incompetence is that they don't have the competence to know that their incompetence is straightforward to verify by a competent person.
root-parent [3 hidden]5 mins ago
You just described every single vibe coder...
thimabi [3 hidden]5 mins ago
I wouldn’t describe what happened here as incompetence. As a “carioca”, I am pleasantly surprised to know that the government’s IT department is involved in AI work — even without the budget to create its own models from scratch.
arcticfox [3 hidden]5 mins ago
This seems kind of insane though, every time I go to Rio I think of the potential of AI/technology to solve some problems and leave it even more paradisiacal... But working on their own model? Wtf? There are a million applications of existing ones there that should be followed up on instead.
carlosjobim [3 hidden]5 mins ago
Why would they care? They get their salaries and pensions and bonuses, and the tax payer is footing the bill.
MadrasTh0rn [3 hidden]5 mins ago
Not surprised
AnotherGoodName [3 hidden]5 mins ago
This is fascinating that it worked though. Can we just merge all the open weight models and get something better?
wds [3 hidden]5 mins ago
I imagine it'd work the same as merging all the good-tasting foods to get an even tastier one
avereveard [3 hidden]5 mins ago
most merge improve a small subset of "feeling" benchmark (too small, too specific, or out of distribution) and tend to show degradation on actual benchmark, with especially punishing result on long chain benchmarks.

also only work on matching architectures (i.e. finetunes/loras of the same model)

dindunuf [3 hidden]5 mins ago
that kinda worked in llama 1/2 era, not between different models but between finetunes of the same model. the briefly legendary Mythomax was IIRC a merge of 5+ tunes, some of which were merges themselves.
_3u10 [3 hidden]5 mins ago
No, they need the same arch, but you can distill them into a single model. And yes, if you use the API directly Claude will often say it’s an open weight model (likely the ones it was distilled from)
yieldcrv [3 hidden]5 mins ago
Didn’t the last thread about this have someone from the lab or an enthusiast in Rio saying exactly that?

Its a fine tune of Qwen

Not a conspiracy

daemonologist [3 hidden]5 mins ago
The allegation here is that it's not actually a fine-tune of Qwen, but instead an undisclosed mashup (merge) of someone else's fine-tune of Qwen and the original model. Rio subsequently said that the model was in fact a merge, that they did additional fine-tuning after the merge, and that they accidentally uploaded the base merge instead of the version with additional fine-tuning. But this seems like quite an oversight...
elzbardico [3 hidden]5 mins ago
[flagged]
guiraldelli [3 hidden]5 mins ago
Without evidence, your comment is just bad mouthing.

I have been involved in academia, including in Brazil, and I don't find academia there any more copycat than any other institution, including top tier ones.

boca_honey [3 hidden]5 mins ago
This is very easy to prove [1][2]. Brazil has that reputation in the broarder academic world, and it's for a reason.

[1] https://www.sciencedirect.com/science/article/abs/pii/S17511...

[2] https://www.scielo.br/j/aabc/a/xNytDrrrHdyK4XPcHBRJZmd/?lang...

dghlsakjg [3 hidden]5 mins ago
This was a municipality working with a government associated IT company.

What does it have to do with Brazilian academia?

_3u10 [3 hidden]5 mins ago
No, typically Brazilians go to Paraguay for their education, most of their technology comes from Paraguay too.
knuppar [3 hidden]5 mins ago
that's just a lie lol, stop spreading misinformation
cassiogo [3 hidden]5 mins ago
What? Never heard of this
stymaar [3 hidden]5 mins ago
That sounds like nonsense, they don't even speak the same language in Brasil and Paraguay …
alfiedotwtf [3 hidden]5 mins ago
Wasn’t it already obvious given the awfully familiar parameter numbers?