physics.integrators — net.clojars.helsingin/physics 0.1.4

Deterministic numerical integrators for state propagation.

rk4 clj

(rk4 {:keys [derivative initial-state t0 dt steps events store?]
      :or {t0 0.0 store? false}})

Classical Runge-Kutta (order 4) for fixed step problems.

Options map: :derivative function (t state) -> state derivative vector :initial-state vector of initial state values :t0 initial time :dt step size (seconds) :steps number of steps to integrate :events optional map of {id event-fn} where event-fn(t, state) -> double :store? if true, retains history for inspection

Returns {:state final-state :time final-time :history [...] :event {:id .. :time .. :state ..}}

rkf45 clj

(rkf45 {:keys [derivative initial-state t-span rtol atol h-init events store?]
        :or {rtol 1.0E-6 atol 1.0E-9 store? false}})

Adaptive fifth-order Runge-Kutta-Fehlberg integrator.

Options map: :derivative (t state) -> derivative vector :initial-state vector :t-span [t0 tf] :rtol relative tolerance :atol absolute tolerance :h-init optional initial step size

Returns {:state final-state :time tf :steps history :event {:id .. :time .. :state ..}}.

rkf45-coefficients clj