On Mar 2, 2013, at 11:16 AM, "Mark F. Adams" <mark.adams at columbia.edu> wrote:
>> >> An alternative description for the method in the paper is "two-level >> unsmoothed aggregation applied to the ASM-preconditioned operator". >> > > Isn't this paper just doing two level unsmoothed aggregation with a V(0,k) > cycle, where k (and the smoother) is K in the paper? > > It looks to me like you are moving the multigrid coarse grid correction > (projection) from the PC into the operator, in which case this method is > identical to two level MG with the V(0,k) cycle. Well, its not "identical" is it? In the deflation approach it introduces a null space into the operator, in the multigrid approach it does not. So identical only in analogy? So what I am interested in EXACTLY how are they related, relationship between eigenvalues or convergence rate. Barry > > I'm sure I'm missing something. Jie's writeup has an orthogonality condition > on the restriction operator, which I don't see in the Vuik paper.
