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Omar Khattab

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@lateinteraction

prof @MIT CSAIL | ColBERT, DSPy.ai (@DSPyOSS), GEPA, RLMs, Pedagogical RL
Cambridge, MA omarkhattab.com Joined December 2022
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Omar Khattab Verified account @lateinteraction
Never felt closer to a fundamental change in how we build retrievers, and a different kind of memory for agents.

ARI is basically test-time training for retrievers, where gradients derived from a reasoning model's preferences teach the retriever where to look *at search time*.

Lots more to do here to get oblique search queries as manageable as non-oblique ones, and that will include first figuring out sub-linear (late-interaction-esque) search.

But the path ahead has never been clearer. Read @dianetc_'s blog!
Diane Verified account @dianetc_ 2d
Is there a way to scale a reasoning model’s judgment for searching a massive corpus?

We introduce the Amortized Reasoning Index (ARI), a new kind of retriever that updates its weights during search, using gradients derived at inference time from the ranking preferences of a reasoning model.

Every session, current agents spend lots of reasoning deciding which search results matter, and then throw all of that judgment away upon compaction. ARI is our attempt to “amortize” that judgment, so that reasoning spent on past queries keeps improving search on future ones.

With no relevance labels, ARI takes a 400M cross-encoder that starts out weak and grows its Recall@100 on held-out queries by up to 7×, ending above Qwen3-Embedding-8B on various oblique/reasoning-intensive search tasks.

Read our blogpost: dianetc.com/musings/ari/

Preliminary results and discussions are below!
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Omar Khattab Verified account @lateinteraction
So proud and grateful to have this support from @gabepereyra @nikogrupen and team at @harvey - long been a fan of their open sharing of contributions in this space like LAB and extremely early ventures into post-training RLMs!

As the capability of weight space programming begins to take shape and evals for it pop up (stay tuned!), I believe it will carry the highest odds at changing our notions of optimization and learning the most, and perhaps resolving the bottlenecks of deep learning that we simply accepted so far, like terrible sample efficiency.

A ton of work to be done here - watch for it from @rikiyatakehi and @jayden_teoh_ in the coming weeks.
Gabe Pereyra Verified account @gabepereyra 4d
Very cool work from @rikiyatakehi and @lateinteraction's lab at MIT.

They show GPT-6 Astra can read the weights of a Qwen model and update them directly to improve performance.

In early results MATH-500 jumped from 7.9% to 48.1% and it even wrote a Breakout policy from scratch.

The two research questions I'm most excited about are whether this scales from billion-parameter models to trillion-parameter models and which stages of a modern post-training pipeline it could replace.

Today the largest open models are post-trained in several stages. Kimi K3 and DeepSeek-V4 train RL specialists and distill them into one model while GLM-5 and MiniMax-M3 run a chain of RL stages.

We're proud to support Omar's lab and to be working with them to scale this up to larger models and test it on LAB.
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