Analysis of extrapolation cascadic multigrid method (EXCMG)

Based on an asymptotic expansion of finite element, a new extrapolation formula and extrapolation cascadic multigrid method (EXCMG) are proposed, in which the new extrapolation and quadratic interpolation are used to provide a better initial value on refined grid. In the case of triple grids, the error of the new initial value is analyzed in detail. A larger scale computation is completed in PC.