Jiacheng Liu

@liujch1998.bsky.social

🎓 PhD student @uwcse @uwnlp. 🛩 Private pilot. Previously: 🧑‍💻 @oculus, 🎓 @IllinoisCS. 📖 🥾 🚴‍♂️ 🎵 ♠️

How can we better understand how models make predictions and which components of a training dataset are shaping their behaviors? In April we introduced OLMoTrace, a feature that lets you trace the outputs of language models back to their full training data in real time. 🧵

As we’ve been working towards training a new version of OLMo, we wanted to improve our methods for measuring the Critical Batch Size (CBS) of a training run, to unlock greater efficiency. but we found gaps between the methods in the literature and our practical needs for training OLMo. 🧵

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I’m thrilled to share RewardBench 2 📊— We created a new multi-domain reward model evaluation that is substantially harder than RewardBench, we trained and released 70 reward models, and we gained insights about reward modeling benchmarks and downstream performance!

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📢We’re taking your questions now on Reddit for tomorrow’s AMA! Ask us anything about OLMo, our family of fully-open language models. Our researchers will be on hand to answer them Thursday, May 8 at 8am PST.

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The story of OLMo, our Open Language Model, goes back to February 2023 when a group of researchers gathered at Ai2 and started planning. What if we made a language model with state-of-the-art performance, but we did it completely in the open? 🧵

We're excited to round out the OLMo 2 family with its smallest member, OLMo 2 1B, surpassing peer models like Gemma 3 1B or Llama 3.2 1B. The 1B model should enable rapid iteration for researchers, more local development, and a more complete picture of how our recipe scales.

A bar graph comparing average performance (10 Tasks) across OLMo 2 1B, SmolLM2 1.7B, Gemma 3 1B, Llama 3.2 1B, and Qwen 2.5 1.5B. The highest performance is 42.7, achieved by OLMo 2 1B.

Have questions? We’re an open book! We’re excited to host an AMA to answer your Qs about OLMo, our family of open language models. 🗓️ When: May 8, 8-10 am PT 🌐 Where: r/huggingface 🧠 Why: Gain insights from our expert researchers Chat soon!

Ask Us Anything about our Open Language Model, OLMo

"OLMoTrace is a breakthrough in AI development, setting a new standard for transparency and trust. We hope it will empower researchers, developers, and users to build with confidence—on models they can understand and trust." - CEO Ali Farhadi at tonight's chat with Karen Dahut #GoogleCloudNext

Ali Farhadi speaking on stage at a fireside chat

Today we're unveiling OLMoTrace, a tool that enables everyone to understand the outputs of LLMs by connecting to their training data. We do this on unprecedented scale and in real time: finding matching text between model outputs and 4 trillion training tokens within seconds. ✨

Ai2@ai2.bsky.social · last yr.

For years it’s been an open question — how much is a language model learning and synthesizing information, and how much is it just memorizing and reciting? Introducing OLMoTrace, a new feature in the Ai2 Playground that begins to shed some light. 🔦

For years it’s been an open question — how much is a language model learning and synthesizing information, and how much is it just memorizing and reciting? Introducing OLMoTrace, a new feature in the Ai2 Playground that begins to shed some light. 🔦

📰Google Cloud moves deeper into open source AI with Ai2 partnership: “Many were wary of using AI models unless they had full transparency into models’ training data and could customize the models completely. Ai2’s models allow that.”

As infini-gram surpasses 500 million API calls, today we're announcing two exciting updates: 1. Infini-gram is now open-source under Apache 2.0! 2. We indexed the training data of OLMo 2 models. Now you can search in the training data of these strong, fully-open LLMs. 🧵 (1/4)

Buckle your seatbelt — we've released the OLMo 2 paper to kick off 2025 🔥. Including 50+ pages on 4 crucial components of the LLM development pipeline.

A list of paper authors for 2 OLMo 2 Furious.

kicking off 2025 with our OLMo 2 tech report while payin homage to the sequelest of sequels 🫡 🚗 2 OLMo 2 Furious 🔥 is everythin we learned since OLMo 1, with deep dives into: 🚖 stable pretrain recipe 🚔 lr anneal 🤝 data curricula 🤝 soups 🚘 tulu post-train recipe 🚜 compute infra setup 👇🧵

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Want to predict the task performance of LMs before pretraining them? We develop task scaling laws and model ladders, which predict the accuracy on individual tasks by OLMo 2 7B & 13B models within 2 points of absolute error. The cost is 1% of the compute used to pretrain them.

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