arXiv Machine Learning By Yasuaki Sumita, Tomoharu Iwata, Toshiyuki Tanaka

Controlling the Diversity-Quality Trade-Off of LLMs by Merging Models Before and After Alignment

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The paper proposes a depth‑aware FrankenMerging technique that blends lower layers of an aligned large language model (LLM) with higher layers of its base counterpart to balance diversity and quality without extra training. Experiments demonstrate that adjusting the layer split controls both lexical and semantic diversity, often surpassing the aligned model in semantic diversity and outperforming temperature sampling in most settings. The method is validated by an ablation that reverses the merge order, supporting the hypothesis about layer‑specific diversity contributions.

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