connorandClaude Opus 5
639c8dcb32
Five conversions panicked on a condition the caller may have no control over: elements from a non-inertial state, geodetic coordinates from a non-body-fixed one, a look direction across frames, and equinoctial elements for a retrograde orbit. Inclination and frame are data, so a catalog with a retrograde object or a state read from a file would abort the process. ConversionError covers the three cases, and reads as a failure of the value rather than of the code. FrameError stays for a rotation that could not be produced, which is a different thing. The four should_panic tests became error assertions, which say more than they did: the retrograde one now also checks that Keplerian elements still work, since that is the fallback the error leaves open. The debug_asserts in state_derivative are untouched. ordinary-diffeq's right-hand side returns SVector and not Result, so a derivative cannot report anything; moving those checks to assembly time is filed separately. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01M9aqCoSmjgoaTbewDHAZhh
74 lines
2.1 KiB
Rust
74 lines
2.1 KiB
Rust
//! Two-body propagation over one orbital period.
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//!
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//! Run with `cargo run --example two_body`.
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use astrokit::prelude::*;
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use nalgebra::Vector3;
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fn main() -> Result<(), Box<dyn std::error::Error>> {
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let epoch = Epoch::from_gregorian_utc_hms(2026, 1, 1, 0, 0, 0);
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let frame = Frame::EARTH_J2000;
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let initial = Cartesian::new(
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Vector3::new(
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4.263868426884883e6,
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5.146189057155391e6,
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1.1310208421331816e6,
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),
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Vector3::new(-5923.454461876975, 4496.802639690076, 1870.3893008991558),
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frame,
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);
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let elements = initial.keplerian()?;
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let period = Duration::from_seconds(initial.period()?);
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let forces = vec![TwoBody { body: Body::EARTH }];
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let mut propagation = Propagation::from_cartesian(epoch, initial, &forces)
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.duration(period)
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.accuracy(Accuracy::High);
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let solution = propagation.run();
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let end = Orbit
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.state(*solution.states.last().unwrap())
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.cartesian(frame);
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println!("epoch: {epoch}");
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println!("body: {}", initial.frame.center.name());
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println!("period: {period}");
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println!(
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"elements: a = {:.3} km, e = {:.6}, i = {:.3} deg ({:?})",
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elements.semi_major_axis / 1e3,
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elements.eccentricity,
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elements.inclination.to_degrees(),
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elements.degeneracy
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);
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println!(
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"altitude: {:.3} km",
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initial.spherical_altitude() / 1e3
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);
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println!("steps: {}", solution.states.len() - 1);
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println!(
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"position error: {:.3e} m",
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(end.position - initial.position).norm()
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);
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println!(
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"velocity error: {:.3e} m/s",
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(end.velocity - initial.velocity).norm()
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);
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println!(
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"energy drift: {:.3e} J/kg",
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end.specific_energy() - initial.specific_energy()
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);
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// Dense output: the state at any time in the arc, not only at a step.
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let half = Orbit
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.state(solution.interpolate(period.to_seconds() / 2.0))
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.cartesian(frame);
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println!(
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"half a period: {:.3} km altitude",
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half.spherical_altitude() / 1e3
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);
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Ok(())
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}
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