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Ali Shokri Shokri

Ali Shokri Shokri

Academic rank: Professor
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Education: PhD.
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Faculty: 1
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Research

Title
Variable Step Hybrid Block Method for the Approximation of Kepler Problem
Type
JournalPaper
Keywords
hybrid method; Kepler’s equation; Lagrange polynomial; stiff; variable step size
Year
2022
Journal Fractal and Fractional
DOI
Researchers Joshua Sunday ، Ali Shokri Shokri ، Daniela Marian

Abstract

In this article, a variable step size strategy is adopted in formulating a new variable step hybrid block method (VSHBM) for the solution of the Kepler problem, which is known to be a rigid and stiff differential equation. To derive the VSHBM, the step size ratio r is left the same, halved, or doubled in order to optimize the total number of steps, minimize the number of formulae stored in the code, and ensure that the method is zero-stable. The method is formulated by integrating the Lagrange polynomial with limits of integration selected at special points. The article further analyzed the stability, order, consistency, and convergence properties of the VSHBM. The stability regions of the VSHBM at different values of the step size ratios were also plotted and plots showed that the method is fit for solving the Kepler problem. The results generated were then compared with some existing methods, including the MATLAB inbuilt stiff solver (ode 15 s), with respect to total number of failure steps, total number of steps, total function calls, maximum error, and computation time.