Callbacks

Callbacks are lightweight per-step hooks that fire around the algorithm's core step. They can inspect or mutate integrator state (e.g. reflect a pair that has passed through a collision singularity) without being fused into the algorithm itself.

Abstract interface

WeberElectrodynamics.HamiltonianCallback — Type

HamiltonianCallback

Abstract supertype for per-step callbacks applied by the integrator. Concrete subtypes can override any of:

apply_pre_step!(cb, integrator, dt_step) — invoked before the algorithm's _step_core! advances the state.
apply_post_step!(cb, integrator, dt_step) — invoked after the state and history have been updated.

Both default to no-ops. Callbacks are type-stably iterated from a tuple stored on the integrator; there is no per-step allocation for an empty callback set.

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WeberElectrodynamics.apply_pre_step! — Function

apply_pre_step!(cb::HamiltonianCallback, integrator, dt_step)

Invoked on the integrator's q/p state immediately before _step_core!(integrator, alg, dt_step) for the upcoming macro step. Default implementation is a no-op.

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WeberElectrodynamics.apply_post_step! — Function

apply_post_step!(cb::HamiltonianCallback, integrator, dt_step)

Invoked after the algorithm's step has completed and history has been recorded. Default implementation is a no-op.

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Built-in callbacks

WeberElectrodynamics.CollisionBounce — Type

CollisionBounce(radius)

Pre-step callback that reflects the relative coordinate of any pair closer than radius through the origin, preserving COM and momenta (C⁰-continuation of the ℓ = 0 head-on collision; Frauenfelder & Weber 2024). Works best with the unregularized symplectic path; LC regularization can drift the bounce.

See docs/exploratory/CollisionBounceRegularization.md for the full physics motivation and validation.

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