There are numerous models in the form of ordinary differential equations
that require numerical treatment, for they have no closed-form solutions
due to some reasons, including non-linearity, stiffness, singularity,
and stability. Having in mind the increasing demand for efficient and
cost-effective algorithms yet straightforward to code; an attempt is
made in this research paper to introduce a new time-efficient optimal
exponentially fitted numerical algorithm whose qualitative analysis
unfolds its local truncation error, zero-stability, A-stability,
consistency, convergence, and accuracy (at least third-order). The
proposed algorithm is also implemented in an adaptive step-size mode,
whereas both constant and adaptive approaches outperform several
existing algorithms when tested upon differential models taken from
applied sciences. The efficiency curves further confirm the
time-effectiveness of the proposed exponentially fitted one-step optimal
method.