Orbit picker: functions to calculate forces and Roche limits

[?]

Jun 16, 2021, 3:21 AM

44YVVUNCI6DMMP6SF7LCBGWDYFAENLRKZ5TUMRSB62YOCL5QXBLAC

Dependencies

[2] PNOS6DEI Orbit picker: move vector stuff to its own module and add more impls
[3] EWUP525B Basic vector arithmetic for the orbit picker
[4] K3V2JNKC Initialize sub-project for choosing lunar orbital parameters
[5] 4LTVYHHI Add async runtime for the orbital parameter picker

Change contents

replacement in orbitpick/src/vec3.rs at line 1

[2.10]→[2.11:39](∅→∅)

#[derive(Copy,Clone,Debug)]

[2.10]

[2.39]

#[derive(Copy, Clone, Debug, PartialEq)]
replacement in orbitpick/src/vec3.rs at line 5

[2.87]→[2.87:102](∅→∅)

pub z: f64

[2.87]

[2.102]

pub z: f64,
replacement in orbitpick/src/vec3.rs at line 103

[2.2030]→[2.2030:2093](∅→∅)

(self.x*self.x + self.y*self.y + self.z*self.z).sqrt()

[2.2030]

[2.2093]

(self.x * self.x + self.y * self.y + self.z * self.z).sqrt()
file addition: nbody.rs (----------)

[3.19]

use crate::vec3::V3;
use std::f64::consts::PI;

pub const G: f64 = 6.67430e-11;

#[derive(Debug, Clone, Copy)]
pub struct Body {
pub mass: f64,
pub position: V3,
pub velocity: V3,
pub radius: f64,
}

impl Body {
pub fn momentum(&self) -> V3 {
self.velocity * self.mass
}

pub fn density(&self) -> f64 {
self.mass / (4. / 3. * PI * self.radius * self.radius * self.radius)
}

pub fn roche_limit(&self, other: &Self, variant: RocheLimitType) -> f64 {
self.radius
* (2. * self.density() / other.density()).powf(1. / 3.)
* match variant {
RocheLimitType::Rigid => 1.,
RocheLimitType::Fluid => 2.44,
}
}
}

pub enum RocheLimitType {
Rigid,
Fluid,
}

pub fn forces(state: Vec<Body>) -> Vec<V3> {
let mut result = vec![
V3 {
x: 0.,
y: 0.,
z: 0.
};
state.len()
];
for (ix, xb) in state.iter().enumerate() {
for (iy, yb) in state.iter().enumerate() {
if ix != iy {
let d = yb.position - xb.position;
let r2 = d.x * d.x + d.y * d.y + d.z * d.z;
let f = xb.mass * yb.mass / r2;
result[ix] += d.normalize() * f;
}
}
}
for b in result.iter_mut() {
*b *= G;
}
result
}
edit in orbitpick/src/main.rs at line 3

[3.466]

[2.2414]

mod nbody;
replacement in orbitpick/src/main.rs at line 9

[3.45]→[3.43:74](∅→∅),[3.43]→[3.43:74](∅→∅)

println!("Hello, world!");

[3.45]

[3.74]

println!("{}", nbody::G);