Improving SAM Requires Rethinking its Optimization Formulation

Fuente: arXiv
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Main Authors: Xie, Wanyun, Latorre, Fabian, Antonakopoulos, Kimon, Pethick, Thomas, Cevher, Volkan
Format: Preprint
Published: 2024
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author Xie, Wanyun
Latorre, Fabian
Antonakopoulos, Kimon
Pethick, Thomas
Cevher, Volkan
author_facet Xie, Wanyun
Latorre, Fabian
Antonakopoulos, Kimon
Pethick, Thomas
Cevher, Volkan
contents This paper rethinks Sharpness-Aware Minimization (SAM), which is originally formulated as a zero-sum game where the weights of a network and a bounded perturbation try to minimize/maximize, respectively, the same differentiable loss. To fundamentally improve this design, we argue that SAM should instead be reformulated using the 0-1 loss. As a continuous relaxation, we follow the simple conventional approach where the minimizing (maximizing) player uses an upper bound (lower bound) surrogate to the 0-1 loss. This leads to a novel formulation of SAM as a bilevel optimization problem, dubbed as BiSAM. BiSAM with newly designed lower-bound surrogate loss indeed constructs stronger perturbation. Through numerical evidence, we show that BiSAM consistently results in improved performance when compared to the original SAM and variants, while enjoying similar computational complexity. Our code is available at https://github.com/LIONS-EPFL/BiSAM.
format Preprint
id arxiv_https___arxiv_org_abs_2407_12993
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Improving SAM Requires Rethinking its Optimization Formulation
Xie, Wanyun
Latorre, Fabian
Antonakopoulos, Kimon
Pethick, Thomas
Cevher, Volkan
Machine Learning
This paper rethinks Sharpness-Aware Minimization (SAM), which is originally formulated as a zero-sum game where the weights of a network and a bounded perturbation try to minimize/maximize, respectively, the same differentiable loss. To fundamentally improve this design, we argue that SAM should instead be reformulated using the 0-1 loss. As a continuous relaxation, we follow the simple conventional approach where the minimizing (maximizing) player uses an upper bound (lower bound) surrogate to the 0-1 loss. This leads to a novel formulation of SAM as a bilevel optimization problem, dubbed as BiSAM. BiSAM with newly designed lower-bound surrogate loss indeed constructs stronger perturbation. Through numerical evidence, we show that BiSAM consistently results in improved performance when compared to the original SAM and variants, while enjoying similar computational complexity. Our code is available at https://github.com/LIONS-EPFL/BiSAM.
title Improving SAM Requires Rethinking its Optimization Formulation
topic Machine Learning
url https://arxiv.org/abs/2407.12993