Hugging Face Daily PapersYecheng Wu, Song Han, Han Cai1 min readpaperadvanced
Lightning Weave: Improving the Accuracy-Efficiency Frontier of Reasoning Models through Capability Composition
Summary
Lightning Weave is a post‑training framework that composes specialist capabilities from separate models into one student via on‑policy distillation, improving both accuracy and token efficiency on math and code benchmarks.
- Lightning Weave extracts specialist capabilities from independently post‑trained models and merges them into a single student via on‑policy distillation.
- Each capability is encoded as a log‑ratio policy shift; aligned shifts at shared token states are turned into stable targets using Tilted‑Target DOPD.
- Anchor trajectories are cached and scored once, eliminating the need to run multiple live specialist models during student training.
- On Qwen3.5‑4B, HMMT 2025 accuracy rises from 59.2% to 64.0% with 10.7% fewer response tokens; LiveCodeBench v5 accuracy jumps to 54.2% from 41.7% with 9.6% token reduction.
LLM engineers looking to boost reasoning performance while cutting inference cost can adopt Lightning Weave to get higher accuracy with fewer tokens.
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