Figure 2From: A fast implicit difference scheme for a new class of time distributed-order and space fractional diffusion equations with variable coefficientsSpectrum of original matrix (red) and preconditioned matrix (blue) for Example 5.1 at time level (a): \(k=0\) and (b): \(k=1\), respectively, when \(M = N = 128\), \(\alpha = 0.5\), \(q = 10\), \(\beta = 1.8\), and \(T = 0.75\)Back to article page