Table 5: Information of preconditioned GMRES(16) method by using different versions of IULBF preconditioner.

MethodIULBF1IULBF2IULBF3IULBF4

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

hor-131 3 34.969 3 63.344 2 26.828 1 63.328
sherman2 + + + + + + 1 1265.38
cavity05 3 1600.69 2 1891.52 3 808.703 1 2074.26
cavity06 3 668.093 2 1872.95 3 795.438 1 1339.13
sherman4 3 792.609 2 874.141 2 462.016 2 626.094
epb0 24 1142.06 23 3673.17 22 1025.64 22 3010.25
pde2961 3 7376.75 3 15940.3 2 4648.44 1 9449.7