On rotated grid point iterative method for solving 2D fractional reaction-subdiffusion equation with Caputo-Fabrizio operator

In this paper, the Crank-Nicolson (CN) and rotated four-point Fractional Explicit Decoupled Group (FEDG) methods are introduced to solve the two-dimensional reaction-subdiffusion equation with Caputo-Fabrizio operator. The FEDG method is derived by 45 degrees rotation of CN method around the x and y axes. The restarted GMRES with left preconditioner L, based on incomplete LU factorization is used to solve the discretized system obtained by our proposed methods. The FEDG method shows more superior capability in the term of CPU timings and the number of iteration compared to CN method on the standard grid but with same order of accuracy. The stability and convergence analysis in the approximate schemes are investigated. Somenumerical experiments performed to show the efficiency of the presented methods in terms of accuracy and CPU time.