Module nyx_space::propagators

Provides all the propagators / integrators available in nyx.

Full example

extern crate nalgebra;
extern crate nyx_space as nyx;
use nalgebra::{U1, U3, Vector6};

fn two_body_dynamics(_t: f64, state: &Vector6<f64>) -> Vector6<f64> {
    let radius = state.fixed_slice::<U3, U1>(0, 0);
    let velocity = state.fixed_slice::<U3, U1>(3, 0);
    let body_acceleration = (-398_600.441500000015366822 / radius.norm().powi(3)) * radius;
    Vector6::from_iterator(velocity.iter().chain(body_acceleration.iter()).cloned())
}

fn main() {
    use std::f64;
    use nyx::propagators::{Dormand45, Options, Propagator};
    // Initial spacecraft state
    let mut state =
        Vector6::from_row_slice(&[-2436.45, -2436.45, 6891.037, 5.088611, -5.088611, 0.0]);
    // Final expected spaceraft state
    let rslt = Vector6::from_row_slice(&[
        -5971.194191668567,
        3945.5066531626767,
        2864.636618498951,
        0.04909695770740798,
        -4.185093318527218,
        5.848940867713008,
    ]);

    let mut cur_t = 0.0;
    let mut iterations = 0;
    let mut prop = Propagator::new::<Dormand45>(&Options::with_adaptive_step(0.1, 30.0, 1e-12));
    loop {
        let (t, state_t) = prop.derive(cur_t, &state, two_body_dynamics);
        iterations += 1;
        cur_t = t;
        state = state_t;
        if cur_t >= 3600.0 * 24.0 {
            let details = prop.latest_details();
            if details.error > 1e-2 {
                assert!(
                             details.step - 1e-1 < f64::EPSILON,
                             "step size should be at its minimum because error is higher than tolerance: {:?}",
                             details
                         );
            }
            println!("{:?}", prop.latest_details());
            assert_eq!(state, rslt, "geo prop failed");
            assert_eq!(iterations, 864_000, "wrong number of iterations");
            break;
        }
    }
}

Re-exports

pub use super::RK;

Structs

CashKarp45	CashKarp45 is a Runge Kutta Cash Karp integrator.
Dormand45	Dormand45 is a Dormand-Prince integrator.
Dormand78	Dormand78 is a Dormand-Prince integrator.
Fehlberg45	Fehlberg45 is a Runge Kutta Fehlberg integrator.
Fehlberg56	Fehlberg56 is a Runge Kutta Fehlberg integrator.
IntegrationDetails	Stores the details of the previous integration step of a given propagator. Access as my_prop.clone().latest_details().
Options	Options stores the integrator options, including the minimum and maximum step sizes, and the max error size.
Propagator	Includes the options, the integrator details of the previous step, and the set of coefficients used for the monomorphic instance. WARNING: must be stored in a mutuable variable.
RK89	RK89 is a Runge Kutta 8-9 integrator.
RK4Fixed	RK4Fixed is a fixed step RK4.
Verner56	Verner56 is an RK Verner integrator of order 5-6.

Traits

RK	The RK trait defines a Runge Kutta integrator.