The Mixed Finite Element Multigrid Method for Stokes Equations

Table 4

Number of iterations and CPU time for multigrid (-cycle) with different smoothers and smoother preconditioner approximations at different levels of refinement, tolerance = .

Levels	MG--cycle()
	DGS	IUzawa	Braess-Sarazin	PMINRES
	Iter(cpu time (sec))	Iter(cpu time (sec))	Iter(cpu time (sec))	Iter(cpu time (sec))
	18 ()	13 ()	9 ()	14 ()
	19 ()	14 ()	10 ()	16 ()
	19 ()	14 ()	11 ()	16 ()
	19 ()	14 ()	11 ()	16 ()