arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2108.06808cs.LG
收藏

可分数据下Bregman邻近点算法与镜像下降的隐式正则化

Implicit Regularization of Bregman Proximal Point Algorithm and Mirror Descent on Separable Data

Georgia Institute of Technology(佐治亚理工学院);Duke University(杜克大学)

Yan Li, Caleb Ju, Ethan X. Fang, Tuo Zhao

AI总结:

该研究针对Bregman邻近点算法(BPPA)理论研究不足的问题,分析可分数据下BPPA的隐式正则化特性,给出间隔下界并证明其与条件数的紧依赖,同时拓展到镜像下降并通过实验验证,填补了算法正则化领域的相关空白。

摘要:

Bregman邻近点算法(BPPA)在机器学习中的应用日益广泛,但其理论研究仍十分欠缺。我们通过在可分数据上学习线性分类器,研究BPPA的计算特性,并证明其具备可证的算法正则化效应。对于任意采用固定Bregman散度的BPPA实例,我们给出了该算法在任意选定范数下所得间隔的下界。该间隔下界与最大间隔相差一个乘性因子,该因子与对偶范数下距离生成函数的条件数成反比。我们证明了这种对条件数的依赖是紧的,从而说明散度对所学分类器的质量有重要影响。我们进一步将研究结论拓展到镜像下降,建立了其间隔与Bregman散度的类似关联,并给出了非渐近分析。我们在合成数据集与真实数据集上开展了数值实验,验证了理论结论的正确性。据我们所知,上述发现在算法正则化领域的现有文献中尚属首次。

英文摘要:

Bregman proximal point algorithm (BPPA) has witnessed emerging machine learning applications, yet its theoretical understanding has been largely unexplored. We study the computational properties of BPPA through learning linear classifiers with separable data, and demonstrate provable algorithmic regularization of BPPA. For any BPPA instantiated with a fixed Bregman divergence, we provide a lower bound of the margin obtained by BPPA with respect to an arbitrarily chosen norm. The obtained margin lower bound differs from the maximal margin by a multiplicative factor, which inversely depends on the condition number of the distance-generating function measured in the dual norm. We show that the dependence on the condition number is tight, thus demonstrating the importance of divergence in affecting the quality of the learned classifiers. We then extend our findings to mirror descent, for which we establish similar connections between the margin and Bregman divergence, together with a non-asymptotic analysis. Numerical experiments on both synthetic and real-world datasets are provided to support our theoretical findings. To the best of our knowledge, the aforementioned findings appear to be new in the literature of algorithmic regularization.

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。

↑