Fast numerical solution for fractional diffusion equations by exponential quadrature rule

Autor: Hai-Wei Sun, Hong-Kui Pang, Lu Zhang
Rok vydání: 2015
Předmět:
Zdroj: Journal of Computational Physics. 299:130-143
ISSN: 0021-9991
DOI: 10.1016/j.jcp.2015.07.001
Popis: After spatial discretization to the fractional diffusion equation by the shifted Grunwald formula, it leads to a system of ordinary differential equations, where the resulting coefficient matrix possesses the Toeplitz-like structure. An exponential quadrature rule is employed to solve such a system of ordinary differential equations. The convergence by the proposed method is theoretically studied. In practical computation, the product of a Toeplitz-like matrix exponential and a vector is calculated by the shift-invert Arnoldi method. Meanwhile, the coefficient matrix satisfies a condition that guarantees the fast approximation by the shift-invert Arnoldi method. Numerical results are given to demonstrate the efficiency of the proposed method. The matrix of the spatial discretization of the fractional diffusion equation is Toeplitz-like.An exponential quadrature rule is employed to solve the system of ordinary differential equations.The Toeplitz-like matrix exponential is calculated by the shift-invert Arnoldi method.The coefficient matrix satisfies a condition that guarantees the fast approximation by the shift-invert Arnoldi method.Numerical results show the efficiency of the exponential quadrature rule.
Databáze: OpenAIRE