Smoothing and Regularization with Modified Sparse Approximate Inverses

Figure 9

Reconstruction error against iterations for the 1D blur problem of size 𝑛=10³ and band=4 affected by random noise of order 0.1%. 𝐺 has 𝜎=1 (a) and 𝜎=10 (b), respectively. CG is compared to PCG using 𝑀_𝑟 and 𝑀_̃𝑟, respectively, for 𝐺 and 𝐺^𝑇𝐺.

(a) 𝐺 with 𝜎=1

(b) 𝐺 with 𝜎=10