非单调周期随机梯度法

Nonmonotonic Cyclic Stochastic Gradient Method

随机梯度下降方法是机器学习中广泛使用的优化方法, 其中步长的选择是该方法性能表现的重要影响因素。本文将非单调线搜索技巧与周期步长更新框架相结合, 提出了非单调的周期随机梯度法。针对强凸问题、凸问题和非凸问题, 我们分别给出了新算法的收敛性分析。在数值实验中, 提出的新算法与已有算法相比有更优的表现, 且对超参数的改变表现稳定。

The Stochastic Gradient Descent (SGD) method is a widely used optimization method for machine learning, where the selection of the step size is a crucial factor for the performance of SGD. This paper combines the nonmonotonic line search technique with a cyclic update strategy for step size, to propose a nonmonotonic cyclic stochastic gradient method. For strongly convex, convex, and non-convex cases, we provide convergence analyses of the proposed algorithm. In numerical experiments, the proposed algorithm shows better performances compared to existing algorithms and is stable in terms of changes in hyperparameters.