A Hybrid Algorithm Based on Optimal Quadratic Spline Collocation and Parareal Deferred Correction for Parabolic PDEs

Figure 2

Instability regions (blank area) of the PDC method using implicit Euler integrators for both the coarse and fine propagators after 2 iterations (a), 3 iterations (b), 4 iterations (c), and 6 iterations (d). The -axis is and the -axis is , where and .

(a)

(b)

(c)

(d)