Different Versions of ILU and IUL Factorizations Obtained from Forward and Backward Factored Approximate Inverse Processes—Part I

Table 3

Properties of IULBF1, IULBF2, IULBF3, and IULBF4 preconditioners.

Method	IULBF1		IULBF2		IULBF3		IULBF4
	Density	𝑃time	Density	𝑃time	Density	𝑃time	Density	𝑃time
hor-131	0.893352	34.422	1.104017	62.11	1.046628	26.219	1.889527	63.328
sherman2	1.434745	766.187	2.834069	1166.11	0.823720	562.094	1.335498	1263.34
cavity05	0.682030	1596.86	1.478304	1887.42	0.686106	803.25	1.538000	2071.98
cavity06	0.651693	663.953	1.549958	1870.22	0.657894	791.422	1.628745	1337.67
sherman4	1.270470	789.687	1.345483	870.672	1.386952	459.625	2.055203	622.031
epb0	0.850721	1077.48	0.853941	3577.97	1.009274	951.688	1.356775	2924.58
pde2961	1.278642	7344.64	1.357011	15909.7	1.309427	4634.16	2.180871	9440.33