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arXiv 2410.22656cs.LG
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倾斜锐度感知最小化

Tilted Sharpness-Aware Minimization

University of Chicago(芝加哥大学);University of Washington(华盛顿大学)

Tian Li, Tianyi Zhou, Jeffrey A. Bilmes

AI总结:

提出受指数倾斜启发的平滑 SAM 推广 TSAM,用倾斜超参数优先考虑高损失局部解,并通过 Hamiltonian 动力学离散化算法求解,在图像和文本任务上获得更平坦最小值与更优测试性能。

摘要:

锐度感知最小化(Sharpness-Aware Minimization,SAM)已被证明可以通过在损失景观中寻找平坦最小值来提升过参数化模型的泛化性能,其做法是优化邻域内导致最大损失的模型参数。然而,这种最小-最大形式在计算上具有挑战性,尤其是当问题高度非凸时。此外,在寻找平坦最小值时,只关注最坏情况下的局部解而忽略可能存在的许多其他局部解,可能并非最优。在本文中,我们提出 Tilted SAM(TSAM),这是受指数倾斜启发的 SAM 的平滑推广,能够有效地为导致较大损失的局部解赋予更高优先级。TSAM 由倾斜超参数 $t$ 参数化,并在 $t$ 趋近于无穷大时退化为 SAM。我们证明 TSAM 比 SAM 更平滑,因此更易于优化,并且它明确偏好更平坦的最小值。我们开发了受 Hamiltonian 动力学离散化启发的算法来求解 TSAM。实验上,在一系列图像和文本任务中,TSAM 得到了更平坦的局部最小值,并且相较 SAM 和 ERM 基线取得了更优的测试性能。

英文摘要:

Sharpness-Aware Minimization (SAM) has been demonstrated to improve the generalization performance of overparameterized models by seeking flat minima on the loss landscape through optimizing model parameters that incur the largest loss within a neighborhood. Nevertheless, such min-max formulations are computationally challenging especially when the problem is highly non-convex. Additionally, focusing only on the worst-case local solution while ignoring potentially many other local solutions may be suboptimal when searching for flat minima. In this work, we propose Tilted SAM (TSAM), a smoothed generalization of SAM inspired by exponential tilting that effectively assigns higher priority to local solutions that incur larger losses. TSAM is parameterized by a tilt hyperparameter $t$ and reduces to SAM as $t$ approaches infinity. We show that TSAM is smoother than SAM and thus easier to optimize, and it explicitly favors flatter minima. We develop algorithms motivated by the discretization of Hamiltonian dynamics to solve TSAM. Empirically, TSAM arrives at flatter local minima and results in superior test performance than the baselines of SAM and ERM across a range of image and text tasks.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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