Block-iterative subgradient projection algorithm for the convex feasibility problem

Projection algorithm is a general and important method for solving the convex feasibility problem,while in many cases,it is difficult to compute exactly the orthogonal projection.To address this situation,we present two kinds of subgradient projection methods for solving the convex feasibility problem in this paper.Firstly,part the nonlinear system into some subsystems;then construct the approximation projection of the subsystem by the convex combination of the subgradient projections on sets of the subsystem;next,iteration is generated either by sequential block-iterative subgradient projection or by parallel block-iterative subgradient projection,and under some conditions show their convergences.