Federated learning (FL) has been recognized as a rapidly growing research area, where the model is trained over massively distributed clients under the orchestration of a parameter server (PS) without sharing clients' data. This paper delves into a class of federated problems characterized by non-convex and non-smooth loss functions, that are prevalent in FL applications but challenging to handle due to their intricate non-convexity and non-smoothness nature and the conflicting requirements on communication efficiency and privacy protection. In this paper, we propose a novel federated primal-dual algorithm with bidirectional model sparsification tailored for non-convex and non-smooth FL problems, and differential privacy is applied for strong privacy guarantee. Its unique insightful properties and some privacy and convergence analyses are also presented for the FL algorithm design guidelines. Extensive experiments on real-world data are conducted to demonstrate the effectiveness of the proposed algorithm and much superior performance than some state-of-the-art FL algorithms, together with the validation of all the analytical results and properties.

提出了一种用于非凸和非平滑联邦学习问题的新型原始-对偶算法，结合双向模型稀疏化和差分隐私，以保证强隐私，通过真实数据上的大量实验验证了该算法的有效性和比某些最先进的联邦学习算法更出色的性能，并验证了所有分析结果和特性。

保护隐私的联邦原始-对偶学习用于模型稀疏化的非凸和非平滑问题