R&B: Domain Regrouping and Data Mixture Balancing for Efficient Foundation Model Training. - Albert Ge; Tzu-Heng Huang; John Cooper; Avi Trost; Ziyi Chu; Satya Sai Srinath Namburi GNVV; Ziyang Cai; Kendall Park; Nicholas Carl Roberts; Frederic Sala (CoRR, 2025)