A positive and elementary stable nonstandard explicit scheme for a mathematical model of the influenza disease

[EN]In this paper, a nonstandard explicit discretization strategy is considered to construct a new nonstandard finite difference scheme for solving a mathematical model of the influenza disease. The new proposed scheme has some interesting properties such as high accuracy and ease of implementation, as well as some preserving properties of the exact theoretical solution of the SIRC system, like positivity and elementary stability. These characteristics make it suitable for solving efficiently the propose model. We provide some numerical comparisons to illustrate our results

A block hybrid integrator for numerically solving fourth-order Initial Value Problems.

[EN]A Linear Multistep Hybrid Block method with four intra-step grid points is presented for approximating directly the solution of fourth order Initial Value Problems (IVPs). Multiple Finite Difference formulas are derived and combined in a block formulation to form a numerical integrator that provides direct solution to fourth order IVPs over sub-intervals. The properties and convergence of the proposed method are discussed. The superiority of this method over existing methods is established numerically on different test problems