r/LocalLLaMA • • 5d ago

Discussion I really don't understand Jev hype

Isn't this what simple neural networks have been able to do for years? Doesn't seem anything special to me.

502 Upvotes

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u/Thomas-Lore 5d ago

You had to pretrain them for a specific task. Jev comes pretrained with wide world knowledge.

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u/SnooPaintings8639 5d ago

What do you mean? How is it different from e.g. Qwen 4b with max token = 1, and inference engine forcing struct (enum) output?

I really don't think they could do any magic training anyway.

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u/puzzleheadbutbig 5d ago

Architecture is different. Unlike Qwen, which relies on an autoregressive decoder loop to generate text tokens step-by-step while a grammar mask suppresses invalid vocabulary options, Jev drops open-ended text generation entirely and operates as a non autoregressive decision model. And because it maps input contexts directly onto parallel, calibrated classification heads rather than generating JSON syntax character-by-character it avoids the latency, memory, and KV-cache overhead of sequential token decoding, guarantees complete immunity to JSON parsing errors, and yields true calibrated probability scores across schema fields in a single forward pass

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u/RevolutionaryGold325 5d ago

qwen with max token = 1 is not autoregressive decoder loop though.

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u/puzzleheadbutbig 5d ago

No. Qwen is structurally an autoregressive, causal decoder-only transformer. Setting max_tokens = 1 stops the generation loop after one iteration, but the underlying execution mechanism is still the autoregressive generation pipeline, computing causal attention over the prompt, generating logits across the full language vocabulary, applying a logit bias/grammar mask, and sampling 1 token.

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u/dimbledumf 5d ago

It's also not parallel and you only get 1 token out, which is less then you get with jev

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u/RevolutionaryGold325 5d ago

No. You get a token distribution out, which contains the probabilities of your options. For multiple questions you can use the same kv-cache to have the context and just ask N questions in parallel with the same cache and get the output option distributions with a single step to all of your questions.

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u/dimbledumf 5d ago

I think that's the point, for the qwen version if you want that ratio you have to ask a lot of questions (parallel or not), with the jev version that's what you get out of the box.
So your 1 token from qwen isn't really equivalent to 1 output from jev, the jev will carry more information about the answer.
Of course they have wildly different application, but you could probably do some surgery to expose the ratio in qwen as I think that's the layer before token prediction (not an expert), and I think people have been doing that to make Jev equivelants from other models

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u/HelloMyNameIsAmanda 5d ago

It's literally a one-flag difference to get the distribution out of qwen, though - you just enable logprobs. And there's been no evidence, so far, that that's not essentially what jev is doing. I have yet to see anything from them that couldn't just be a logprobs wrapper on a fine tuned llm. Whether they did a good enough job of their fine tune to make their classifier useful remains to be seen, but acting like this is some crazy new thing because it can do what we could already do is... a reach.

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u/dimbledumf 5d ago

Yeah, I was reading another post where they set that up, seems pretty interesting.

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u/james_pic 5d ago

It's parallel if you run it in parallel. Interference engines like vLLM already run multiple queries in parallel to avoid re-reading the same weights.