13. Stepper Data Structure
This section presents the SUNStepper
base class which represents a
generic solution procedure for IVPs of the form
(13.1)\[\dot{v}(t) = f(t, v) + r(t), \qquad v(t_0) = v_0,\]
on an interval \(t \in [t_0, t_f]\). The time dependent forcing term, \(r_i(t)\), is given by
(13.2)\[r(t) = \sum_{k = 0}^{n_{\text{forcing}}-1}
\left( \frac{t - t_{\text{shift}}}{t_{\text{scale}}} \right)^{k} \widehat{f}_k.\]
SUNStepper
provides an abstraction over SUNDIALS integrators, custom
integrators, exact solution procedures, or other approaches for solving
(13.1). These are used, for example, in operator splitting and
forcing methods to solve inner IVPs in a flexible way.