New Preconditioners for Nonsymmetric Saddle Point Systems with Singular (1,1) Block

Table 3

Iteration time and iteration numbers of GMRES of preconditioned matrices 𝒯⁻¹𝒜 and 𝓐⁻¹𝒜 for different 𝑘=2 with nullity =𝑚.

	𝑚+𝑛	300	1200	2028	2700	3675
𝒯^−1𝒜	Time	0.3856	2.7447	11.7693	31.8844	75.5760
	Iter	1	1	1	1	1
𝓐^−1𝒜	Time	0.0752	2.2487	9.3957	20.9046	64.8728
	Iter	1	1	1	1	1