Llama3 pre-training lead. Partially to blame for things like the Cicero Diplomacy bot, BART, RoBERTa, attention sinks, kNN-LM, top-k sampling & Deal Or No Deal.

Joined September 2019
11 Photos and videos
Excited to see what the amazing @sarahookr and team build here!
Beginnings are very special. Today is an important day for @adaptionlabs. Today a handful of one-size-fits-all-models are optimized for the average use case. Averages erase the exceptional. Everything intelligent adapts. So should AI.
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Mike Lewis retweeted
Our team in FAIR at Meta is hiring a (full-time) researcher! We work on the topics of Reasoning, Alignment and Memory/architectures (RAM) for self-improvement & co-improvement. Apply here: metacareers.com/profile/job_โ€ฆ Location: NY, Seattle or Menlo Park. Some of our recent work to give flavor: Co-Improvement (position): arxiv.org/abs/2512.05356 SPICE (Self-Play in Corpus Environments): arxiv.org/abs/2510.24684 Self-Challenging Agents: arxiv.org/abs/2506.01716 RL from Human Interaction: arxiv.org/abs/2509.25137 AggLM (parallel aggregation): arxiv.org/abs/2509.06870 StepWiser (CoT-PRM RL): arxiv.org/abs/2508.19229 DARLING (diversity-trained RL): arxiv.org/abs/2509.02534 J1 (RL-trained LLM-as-Judge): arxiv.org/abs/2505.10320 CoT-Self-Instruct: arxiv.org/abs/2507.23751 Multi-Token Attention: arxiv.org/abs/2504.00927

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Mike Lewis retweeted
8 Oct 2025
๐Ÿš€ Introducing the Latent Speech-Text Transformer (LST) โ€” a speech-text model that organizes speech tokens into latent patches for better textโ†’speech transfer, enabling steeper scaling laws and more efficient multimodal training โšก๏ธ Paper ๐Ÿ“„ arxiv.org/pdf/2510.06195
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Love seeing these incredibly creative new evaluations! Optimizing benchmarks is easy, the real challenge is in generalizing to the tasks that don't exist yet
11 Aug 2025
new post. there's a lot in it. i suggest you check it out
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Mike Lewis retweeted
I've written the full story of Attention Sinks โ€” a technical deep-dive into how the mechanism was developed and how our research ended up being used in OpenAI's new OSS models. For those interested in the details: hanlab.mit.edu/blog/streaminโ€ฆ
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Mike Lewis retweeted
Donโ€™t miss this - Iโ€™ve worked with Mike (@ml_perception) very closely at Meta and his talks are super informative and fun.
Want to learn about Llama's pre-training? Mike Lewis will be giving a Keynote at NAACL 2025 in Albuquerque, NM on May 1. 2025.naacl.org/ @naaclmeeting
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Mike Lewis retweeted
๐Ÿ“‰๐Ÿ“‰NEW SCALING LAW PHENOMENON ๐Ÿ“‰๐Ÿ“‰ We find that knowledge and reasoning exhibit different scaling behaviors! Super excited to finally tell you all about our paper on the compute optimal scaling of skills: arxiv.org/pdf/2503.10061 [1/n]
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Mike Lewis retweeted
โœจNew PreprintโœจWe introduce ๐๐ซ๐š๐ง๐œ๐ก-๐“๐ซ๐š๐ข๐ง-๐’๐ญ๐ข๐ญ๐œ๐ก (๐๐“๐’), an efficient & flexible method for stitching together independently pretrained LLM experts (i.e. code, math) into a single, capable generalist model. Key Takeaways: โœ…BTS achieves the best average generalist performance across a variety of tasks ๐Ÿ‘Š โœ…We stitch together 4 x 2.7B specialized expert LLMs, where only the lightweight stitching layers (<300M params in totalโ€ผ) are trained while the expertsโ€™ params remain frozen. This makes BTS super modular, flexible, and easy to train! ๐Ÿ‘Š arxiv.org/abs/2502.00075 Work done at @AIatMeta w/ @prajjwal_1, Chloe Bi, Chris Cai, @j_foerst @imjeremyhi @punitkoura, Ruan Silva, @shengs1123 @em_dinan* @ssgrn* @ml_perception* * Joint last author ๐Ÿงต๐Ÿ‘‡(1/5)
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Mike Lewis retweeted
๐Ÿš€ Introducing the Byte Latent Transformer (BLT) โ€“ An LLM architecture that scales better than Llama 3 using byte-patches instead of tokens ๐Ÿคฏ Paper ๐Ÿ“„ dl.fbaipublicfiles.com/blt/Bโ€ฆ Code ๐Ÿ› ๏ธ github.com/facebookresearch/โ€ฆ
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Mike Lewis retweeted
How can we reduce pretraining costs for multi-modal models without sacrificing quality? We study this Q in our new work: arxiv.org/abs/2411.04996 At @AIatMeta, We introduce Mixture-of-Transformers (MoT), a sparse architecture with modality-aware sparsity for every non-embedding transformer parameter (e.g., feed-forward networks, attention matrices, and layer normalization). MoT achieves dense-level performance with up to 66% fewer FLOPs! โœ… Chameleon setting (text image generation): Our 7B MoT matches dense baseline quality using just 55.8% of the FLOPs. โœ… Extended to speech as a third modality, MoT achieves dense-level speech quality with only 37.2% of the FLOPs. โœ… Transfusion setting (text autoregressive image diffusion): MoT matches dense model quality using one-third of the FLOPs. โœ… System profiling shows MoT achieves dense-level image quality in 47% and text quality in 75.6% of the wall-clock time** Takeaway: Modality-aware sparsity in MoT offers a scalable path to efficient, multi-modal AI with reduced pretraining costs. Work of a great team with @liliyu_lili, Liang Luo, @sriniiyer88, Ning Dong, @violet_zct, @gargighosh, @ml_perception, @scottyih, @LukeZettlemoyer, @VictoriaLinML.๐Ÿ‘ **Measured on AWS p4de.24xlarge instances with NVIDIA A100 GPUs.
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Mike Lewis retweeted
1/n Introducing MoMa ๐Ÿ–ผ, our new sparse early-fusion architecture for mixed-modal language modeling that significantly boosts pre-training efficiency ๐Ÿš€ (arxiv.org/pdf/2407.21770). MoMa employs a mixture-of-expert (MoE) framework with modality-specific expert groups. Given any interleaved mixed-modal token sequences, each group exclusively processes tokens of the designated modality with conventional MoE routing. This is joint work with amazing co-first authors @AkshatS07, @ArmenAgha and collaborators @AIatMeta โ€“ Liang Luo, @sriniiyer88, @ml_perception, @gargighosh and @LukeZettlemoyer.
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tldr; you can go a long way in pre-training by (1) curating amazing data, (2) using a lot of FLOPs, and (3) otherwise not screwing up. All three are harder than they sound, so read the paper... That said, I'm amazed by our progress since Llama 3 - expect big things from Llama 4!
So excited for the open release of Llama 3.1 405B - with MMLU > 87, it's a really strong model and I can't wait to see what you all build with it! llama.meta.com/ Also check out the paper here, with lots of details on how this was made: tinyurl.com/2z2cpj8m
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So excited for the open release of Llama 3.1 405B - with MMLU > 87, it's a really strong model and I can't wait to see what you all build with it! llama.meta.com/ Also check out the paper here, with lots of details on how this was made: tinyurl.com/2z2cpj8m

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Excited to see the open source release of FAIR's early fusion multimodal LLMs!
18 Jun 2024
Today is a good day for open science. As part of our continued commitment to the growth and development of an open ecosystem, today at Meta FAIR weโ€™re announcing four new publicly available AI models and additional research artifacts to inspire innovation in the community and help advance AI in a responsible way. More in the video from @jpineau1. What weโ€™re releasing: ๐ŸฆŽ Meta Chameleon 7B & 34B language models that support mixed-modal input and text-only outputs. ๐Ÿช™ Meta Multi-Token Prediction Pretrained Language Models for code completion using Multi-Token Prediction. ๐ŸŽผ Meta JASCO Generative text-to-music models capable of accepting various conditioning inputs for greater controllability. Paper available today with a pretrained model coming soon. ๐Ÿ—ฃ๏ธ Meta AudioSeal An audio watermarking model that we believe is the first designed specifically for the localized detection of AI-generated speech, available under a commercial license. ๐Ÿ“ Additional RAI artifacts Including research, data and code to measure and improve the representation of geographical and cultural preferences and diversity in AI systems. We believe that access to state-of-the-art AI creates opportunities for everyone โ€“ not just a small handful of Big Tech companies. Weโ€™re excited to share this work and to see how the community learns, iterates and builds using this technology. Details and access to everything released by FAIR today โžก๏ธ go.fb.me/tzzvfg
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Mike Lewis retweeted
10 May 2024
Thrilled to be in Vienna for our ICLR workshop, Navigating and Addressing Data Problems for Foundation Models. Starting Saturday at 8:50 AM, our program features keynote talks, best paper presentations, a poster session, and a panel discussion. Explore the full schedule here! sites.google.com/view/dpfm-iโ€ฆ
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Mike Lewis retweeted
Introducing Lory, a fully-differentiable MoE arch for decoder LM pre-training! Lory merges expert FFNs by computing a weighted average in the parameter space, and computes the output through the merged FFNs. But training naively is infeasible, how to make it work? Details in๐Ÿงต
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Mike Lewis retweeted
22 Apr 2024
Moreover, we observe even stronger performance in English category, where Llama 3 ranking jumps to ~1st place with GPT-4-Turbo! It consistently performs strong against top models (see win-rate matrix) by human preference. It's been optimized for dialogue scenario with large amount of instruction data in post-training. More analysis still ongoing with topic distribution and agreement study. We also look forward to details in Llama-3's technical report.
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I'm seeing a lot of questions about the limit of how good you can make a small LLM. tldr; benchmarks saturate, models don't. LLMs will improve logarithmically forever with enough good data.
Yes, both the 8B and 70B are trained way more than is Chinchilla optimal - but we can eat the training cost to save you inference cost! One of the most interesting things to me was how quickly the 8B was improving even at 15T tokens.
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Yes, both the 8B and 70B are trained way more than is Chinchilla optimal - but we can eat the training cost to save you inference cost! One of the most interesting things to me was how quickly the 8B was improving even at 15T tokens.
18 Apr 2024
Llama3 8B is trained on almost 100 times the Chinchilla optimal number of tokens
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