RKBS32 (Bogacki-Shampine)

class pathsim.solvers.rkbs32.RKBS32(*solver_args, **solver_kwargs)[source]

Bases: ExplicitRungeKutta

Bogacki-Shampine 3(2) pair. Four-stage, 3rd order with FSAL property.

The underlying method of MATLAB’s ode23. The First-Same-As-Last (FSAL) property makes the effective cost three stages per accepted step.

Characteristics

  • Order: 3 (propagating) / 2 (embedded)

  • Stages: 4 (3 effective with FSAL)

  • Explicit, adaptive timestep

Note

A good default when moderate accuracy suffices and per-step cost matters more than large step sizes. Fewer stages than 5th order pairs, so faster per step but needs more steps for the same global error. In a PathSim block diagram with smooth, non-stiff dynamics and relaxed tolerances this is often the most efficient explicit choice. Switch to RKDP54 when tighter tolerances are required.

References