Beyond Accuracy Optimization: Computer Vision Losses for Large Language Model Fine-Tuning
Daniele Rege Cambrin, Giuseppe Gallipoli, Irene Benedetto, Luca Cagliero, Paolo Garza
TL;DR
This work tackles the efficiency limits of fine-tuning large language models by repurposing segmentation-style losses from computer vision for NLP tasks. By combining these losses with a light LoRA-based fine-tuning regime, the authors show that task-adapted losses such as Focal and Lovász can significantly outperform standard Cross Entropy on Math Word Problems and QA, achieving up to a +42% gain in exact-match without additional data or human feedback. They also demonstrate improved quality of intermediate reasoning steps, with IoU-aligned objectives correlating with reasoning metrics and reducing error types like missing steps. The findings suggest a scalable, data-efficient path for improving LLM performance across structured reasoning tasks, with practical implications for accessible model fine-tuning and broader deployment.
Abstract
Large Language Models (LLMs) have demonstrated impressive performance across various tasks. However, current training approaches combine standard cross-entropy loss with extensive data, human feedback, or ad hoc methods to enhance performance. These solutions are often not scalable or feasible due to their associated costs, complexity, or resource requirements. This study investigates the use of established semantic segmentation loss functions in natural language generation to create a versatile, practical, and scalable solution for fine-tuning different architectures. We evaluate their effectiveness in solving Math Word Problems and question answering across different models of varying sizes. For the analyzed tasks, we found that the traditional Cross-Entropy loss represents a sub-optimal choice, while models trained to minimize alternative (task-dependent) losses, such as Focal or Lovász, achieve a mean improvement of +42% on exact match without requiring additional data or human feedback. These findings suggest a promising pathway for more efficient and accessible training processes.
