Ultraconvergence of the patch recovery technique II

Zhimin Zhang
1999 Mathematics of Computation  
The ultraconvergence property of a gradient recovery technique proposed by Zienkiewicz and Zhu 8] is analyzed for the Laplace equation in the two dimensional setting. Under the assumption that the pollution e ect is not present or is properly controlled, it is shown that the convergence rate of the recovered gradient at an interior node is two orders higher than the optimal global convergence rate when even-order nite element spaces and local uniform rectangular meshes are used.
doi:10.1090/s0025-5718-99-01205-3 fatcat:6t5qrstvkredpbrkws2pb6timq