Further, in Figure 5, we show the good scaling with respect to increasing problem sizes with MG(A-SFP) (which is a usual advantage of an MG method). There we compare the cost per pixel point of MG(A-SFP) with those of the SFP1, SFP2, and A-SFP methods for image sizes of n = 128, 256, 512 (with n2 pixels in each case). Clearly one observes that MG(A-SFP) is scalable with respect to WUs, while the unilevel methods are not.