Task Vector Quantization for Memory-Efficient Model Merging
- URL: http://arxiv.org/abs/2503.06921v1
- Date: Mon, 10 Mar 2025 05:00:24 GMT
- Title: Task Vector Quantization for Memory-Efficient Model Merging
- Abstract summary: We propose quantizing task vectors instead of quantizing fine-tuned checkpoints.<n>Our method maintains or improves model merging performance while using only 8% of the memory required for full-precision checkpoints.
- Score: 11.777982281994193
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Model merging enables efficient multi-task models by combining task-specific fine-tuned checkpoints. However, storing multiple task-specific checkpoints requires significant memory, limiting scalability and restricting model merging to larger models and diverse tasks. In this paper, we propose quantizing task vectors (i.e., the difference between pre-trained and fine-tuned checkpoints) instead of quantizing fine-tuned checkpoints. We observe that task vectors exhibit a narrow weight range, enabling low precision quantization (up to 4 bit) within existing task vector merging frameworks. To further mitigate quantization errors within ultra-low bit precision (e.g., 2 bit), we introduce Residual Task Vector Quantization, which decomposes the task vector into a base vector and offset component. We allocate bits based on quantization sensitivity, ensuring precision while minimizing error within a memory budget. Experiments on image classification and dense prediction show our method maintains or improves model merging performance while using only 8% of the memory required for full-precision checkpoints.
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