Based on the theory developed by [6], it is proven that the W-cycle multigrid method is optimal, i.e., the convergence rate is independent of the mesh size and mesh level.

• 我们提出了一种网格转移算子，在[6]的理论框架下，证明W循环的多重网格法是最优的，既收敛率与网格尺寸及层数无关。