Yi: Open Foundation Models by 01.AI
Authors: name: 01. AI, name: Alex Young, name: Bei Chen, name: Chao Li, name: Chengen Huang, name: Ge Zhang, name: Guanwei Zhang, name: Heng Li, name: Jiangcheng Zhu, name: Jianqun Chen, name: Jing Chang, name: Kaidong Yu, name: Peng Liu, name: Qiang Liu, name: Shawn Yue, name: Senbin Yang, name: Shiming Yang, name: Tao Yu, name: Wen Xie, name: Wenhao Huang, name: Xiaohui Hu, name: Xiaoyi Ren, name: Xinyao Niu, name: Pengcheng Nie, name: Yuchi Xu, name: Yudong Liu, name: Yue Wang, name: Yuxuan Cai, name: Zhenyu Gu, name: Zhiyuan Liu, name: Zonghong Dai

We introduce the Yi model family, a series of language and multimodal models
that demonstrate strong multi-dimensional capabilities. The Yi model family is
based on 6B and 34B pretrained language models, then we extend them to chat
models, 200K long context models, depth-upscaled models, and vision-language
models. Our base models achieve strong performance on a wide range of
benchmarks like MMLU, and our finetuned chat models deliver strong human
preference rate on major evaluation platforms like AlpacaEval and Chatbot
Arena. Building upon our scalable super-computing infrastructure and the
classical transformer architecture, we attribute the performance of Yi models
primarily to its data quality resulting from our data-engineering efforts. For
pretraining, we construct 3.1 trillion tokens of English and Chinese corpora
using a cascaded data deduplication and quality filtering pipeline. For
finetuning, we polish a small scale (less than 10K) instruction dataset over
multiple iterations such that every single instance has been verified directly
by our machine learning engineers. For vision-language, we combine the chat
language model with a vision transformer encoder and train the model to align
visual representations to the semantic space of the language model. We further
extend the context length to 200K through lightweight continual pretraining and
demonstrate strong needle-in-a-haystack retrieval performance. We show that
extending the depth of the pretrained checkpoint through continual pretraining
further improves performance. We believe that given our current results,
continuing to scale up model parameters using thoroughly optimized data will
lead to even stronger frontier models.