Table 4: Information of preconditioned GMRES(16) method by using different versions of ILUFF preconditioner.

MethodILUFF1ILUFF2ILUFF3ILUFF4

𝑖 𝑡 𝑇 time 𝑖 𝑡 𝑇 time 𝑖 𝑡 𝑇 time 𝑖 𝑡 𝑇 time

hor-131 4 23.031 3 45.4868 2 32.922 2 32.984
sherman2 + + + + + + + +
cavity05 + + + + + + 191 2324.7
cavity06 + + + + + + 96 926.188
sherman4 3 270.324 3 810.734 3 322.687 3 577.485
epb0 12978.405 8 2385.63 13 1335.89 8 1795.58
pde2961 4 7027.38 4 10894.7 4 5928.36 3 9294.05