Finite Element Preconditioning on Spectral Element Discretizations for Coupled Elliptic Equations

Figure 6

The eigenvalues of 𝖠_𝑁2(left) and 𝖡_ℎ2⁻¹𝖠_𝑁2(right) for 𝛿=1 (top) and 𝛿=10⁻³ (bottom) when 𝐛=[10,10]^𝑇 and 𝑁=12,𝐸=4.

(a)

(b)

(c)

(d)