Figure 2From: Multigrid method based on transformation-free high-order scheme for solving 2D Helmholtz equation on nonuniform grids Computed solutions through HOC and CDS schemes for problem 1. (a) Exact solution. (b) Computed solution from HOC scheme with uniform grids. (c) HOC scheme on nonuniform grids. (d) CDS scheme on nonuniform grids. The error vector \(e_{ij}=u_{ij}-v_{ij}\), and \(N=32\) is the number of nodes, and \(k=10\) and \(\lambda= -0.8\) for Example 1.Back to article page