A Modified SSOR Preconditioning Strategy for Helmholtz Equations

Table 1

Iteration numbers for the two-dimensional Helmholtz equations for ℎ=1/19 meshes, using COCG with the preconditioner 𝑃_SSOR and 𝑃_MSSOR for solving the complex symmetric indefinite linear systems.

				(p, q)
h	Preconditioner		(800, 10)	(800, 20)	(800, 30)	(800, 40)
1/19	𝑃SSOR	IT	246	242	239	214
		CPU(s)	0.8438	0.8125	0.7813	0.7344
	𝑃MSSOR	IT	138	133	126	117
		CPU(s)	0.25	0.2188	0.2031	0.1875