Numerical solution of multi-order fractional differential equations with multiple delays via spectral collocation methods

Abstract

• A framework for solving multi-delay fractional differential equations is proposed. • Fractional delay differential equations with irrational delays are discretized. • The method possesses spectral convergence with efficient computational time. • The convergence, error estimates, and numerical stability of the method are studied. • Several illustrative practical examples show the advantages of the method. This paper discusses a general framework for the numerical solution of multi-order fractional delay differential equations (FDDEs) in noncanonical forms with irrational/rational multiple delays by the use of a spectral collocation method. In contrast to the current numerical methods for solving fractional differential equations, the proposed framework can solve multi-order FDDEs in a noncanonical form with incommensurate orders. The framework can also solve multi-order FDDEs with irrational multiple delays. Next, the framework is enhanced by the fractional Chebyshev collocation method in which a Chebyshev operation matrix is constructed for the fractional differentiation. Spectral convergence and small computational time are two other advantages of the proposed framework enhanced by the fractional Chebyshev collocation method. In addition, the convergence, error estimates, and numerical stability of the proposed framework for solving FDDEs are studied. The advantages and computational implications of the proposed framework are discussed and verified in several numerical examples.