The effect of step size ratio on 2-point Block Backward Differentiation Formula for solving stiff ODEs

This paper presents the development of fourth-order 2-point variable step block method based on Block Backward Differentiation Formula (BBDF). By varying the distinct values of the step size ratio, we aim to identify numerical solutions for stiff ordinary differential equations (ODEs) of the first order that give rise to the initial value problem (IVP). An advantageous aspect of this approach is that it simultaneously produces two new values during each iteration. The procedure will be adjusted by substituting 1.6 and 1.9 with a step size increased by 1.8. The process of selecting the step size is also involved. Next, a comparison is conducted between the performance step size factor of 1.8 with the factors, 1.6 and 1.9, to assess the impact of altering the step size ratios on the solutions.