tutorials/learn-rust-the-dangerous-way
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Add the last function, mostly working

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This commit is contained in:
Timothy Warren 2020-01-10 16:19:22 -05:00
parent 187359d84f
commit f7198add5e
1 changed files with 140 additions and 48 deletions
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188
src/main.rs
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@ -1,11 +1,7 @@
#![allow(
non_upper_case_globals,
non_camel_case_types,
non_snake_case,
)]
use std::mem;
#![allow(non_upper_case_globals, non_camel_case_types, non_snake_case)]
use std::arch::x86_64::*;
use std::f64::consts::PI;
use std::mem;
#[repr(C)]
struct body {
@ -19,62 +15,67 @@ const DAYS_PER_YEAR: f64 = 365.24;
const BODIES_COUNT: usize = 5;
static mut solar_Bodies: [body; BODIES_COUNT] = [
body { // Sun
body {
// Sun
mass: SOLAR_MASS,
position: [0.; 3],
velocity: [0.; 3],
},
body { // Jupiter
body {
// Jupiter
mass: 9.54791938424326609e-04 * SOLAR_MASS,
position: [
4.84143144246472090e+00,
-1.16032004402742839e+00,
-1.03622044471123109e-01
-1.03622044471123109e-01,
],
velocity: [
1.66007664274403694e-03 * DAYS_PER_YEAR,
7.69901118419740425e-03 * DAYS_PER_YEAR,
-6.90460016972063023e-05 * DAYS_PER_YEAR
]
-6.90460016972063023e-05 * DAYS_PER_YEAR,
],
},
body { // Saturn
body {
// Saturn
mass: 2.85885980666130812e-04 * SOLAR_MASS,
position: [
8.34336671824457987e+00,
4.12479856412430479e+00,
-4.03523417114321381e-01
-4.03523417114321381e-01,
],
velocity: [
-2.76742510726862411e-03 * DAYS_PER_YEAR,
4.99852801234917238e-03 * DAYS_PER_YEAR,
2.30417297573763929e-05 * DAYS_PER_YEAR
]
2.30417297573763929e-05 * DAYS_PER_YEAR,
],
},
body { // Uranus
body {
// Uranus
mass: 4.36624404335156298e-05 * SOLAR_MASS,
position: [
1.28943695621391310e+01,
-1.51111514016986312e+01,
-2.23307578892655734e-01
-2.23307578892655734e-01,
],
velocity: [
2.96460137564761618e-03 * DAYS_PER_YEAR,
2.37847173959480950e-03 * DAYS_PER_YEAR,
-2.96589568540237556e-05 * DAYS_PER_YEAR
]
-2.96589568540237556e-05 * DAYS_PER_YEAR,
],
},
body { // Neptune
body {
// Neptune
mass: 5.15138902046611451e-05 * SOLAR_MASS,
position: [
1.53796971148509165e+01,
-2.59193146099879641e+01,
1.79258772950371181e-01
1.79258772950371181e-01,
],
velocity: [
2.68067772490389322e-03 * DAYS_PER_YEAR,
1.62824170038242295e-03 * DAYS_PER_YEAR,
-9.51592254519715870e-05 * DAYS_PER_YEAR
]
-9.51592254519715870e-05 * DAYS_PER_YEAR,
],
},
];
@ -82,8 +83,7 @@ unsafe fn offset_Momentum(bodies: *mut body) {
for i in 0..BODIES_COUNT {
for m in 0..3 {
(*bodies.add(0)).velocity[m] -=
(*bodies.add(i)).velocity[m]
* (*bodies.add(i)).mass / SOLAR_MASS;
(*bodies.add(i)).velocity[m] * (*bodies.add(i)).mass / SOLAR_MASS;
}
}
}
@ -92,35 +92,29 @@ unsafe fn output_Energy(bodies: *mut body) {
let mut energy = 0.;
for i in 0..BODIES_COUNT {
// Add the kinetic energy for each body.
energy += 0.5 * (*bodies.add(i)).mass * (
(*bodies.add(i)).velocity[0]
* (*bodies.add(i)).velocity[0]
+ (*bodies.add(i)).velocity[1]
* (*bodies.add(i)).velocity[1]
+ (*bodies.add(i)).velocity[2]
* (*bodies.add(i)).velocity[2]);
energy += 0.5
* (*bodies.add(i)).mass
* ((*bodies.add(i)).velocity[0] * (*bodies.add(i)).velocity[0]
+ (*bodies.add(i)).velocity[1] * (*bodies.add(i)).velocity[1]
+ (*bodies.add(i)).velocity[2] * (*bodies.add(i)).velocity[2]);
// Add the potential energy between this body and
// every other body
for j in i+1..BODIES_COUNT {
let mut position_Delta =
[mem::MaybeUninit::<f64>::uninit(); 3];
for j in i + 1..BODIES_COUNT {
let mut position_Delta = [mem::MaybeUninit::<f64>::uninit(); 3];
for m in 0..3 {
position_Delta[m].as_mut_ptr().write(
(*bodies.add(i)).position[m]
- (*bodies.add(j)).position[m]
);
position_Delta[m]
.as_mut_ptr()
.write((*bodies.add(i)).position[m] - (*bodies.add(j)).position[m]);
}
let position_Delta: [f64; 3] =
mem::transmute(position_Delta);
let position_Delta: [f64; 3] = mem::transmute(position_Delta);
energy -= (*bodies.add(i)).mass
* (*bodies.add(j)).mass
energy -= (*bodies.add(i)).mass * (*bodies.add(j)).mass
/ f64::sqrt(
position_Delta[0]*position_Delta[0]+
position_Delta[1]*position_Delta[1]+
position_Delta[2]*position_Delta[2]
position_Delta[0] * position_Delta[0]
+ position_Delta[1] * position_Delta[1]
+ position_Delta[2] * position_Delta[2],
);
}
}
@ -129,6 +123,104 @@ unsafe fn output_Energy(bodies: *mut body) {
println!("{:.9}", energy);
}
fn main() {
println!("Hello, world!");
unsafe fn advance(bodies: *mut body) {
const INTERACTIONS_COUNT: usize = BODIES_COUNT * (BODIES_COUNT - 1) / 2;
const ROUNDED_INTERACTIONS_COUNT: usize = INTERACTIONS_COUNT + INTERACTIONS_COUNT % 2;
#[repr(align(16))]
#[derive(Copy, Clone)]
struct Align16([f64; ROUNDED_INTERACTIONS_COUNT]);
static mut position_Deltas: [Align16; 3] = [Align16([0.; ROUNDED_INTERACTIONS_COUNT]); 3];
static mut magnitudes: Align16 = Align16([0.; ROUNDED_INTERACTIONS_COUNT]);
{
let mut k = 0;
for i in 0..BODIES_COUNT - 1 {
for j in i + 1..BODIES_COUNT {
for m in 0..3 {
position_Deltas[m].0[k] =
(*bodies.add(i)).position[m] - (*bodies.add(j)).position[m];
}
k += 1;
}
}
}
for i in 0..ROUNDED_INTERACTIONS_COUNT / 2 {
let mut position_Delta = [mem::MaybeUninit::<__m128d>::uninit(); 3];
for m in 0..3 {
position_Delta[m]
.as_mut_ptr()
.write(*(&position_Deltas[m].0 as *const f64 as *const __m128d).add(i));
}
let position_Delta: [__m128d; 3] = mem::transmute(position_Delta);
let distance_Squared: __m128d = _mm_add_pd(
_mm_add_pd(
_mm_mul_pd(position_Delta[0], position_Delta[0]),
_mm_mul_pd(position_Delta[1], position_Delta[1]),
),
_mm_mul_pd(position_Delta[2], position_Delta[2]),
);
let mut distance_Reciprocal: __m128d =
_mm_cvtps_pd(_mm_rsqrt_ps(_mm_cvtpd_ps(distance_Squared)));
for _ in 0..2 {
distance_Reciprocal = _mm_sub_pd(
_mm_mul_pd(distance_Reciprocal, _mm_set1_pd(1.5)),
_mm_mul_pd(
_mm_mul_pd(
_mm_mul_pd(_mm_set1_pd(0.5), distance_Squared),
distance_Reciprocal,
),
_mm_mul_pd(distance_Reciprocal, distance_Reciprocal),
),
);
}
(magnitudes.0.as_mut_ptr() as *mut __m128d)
.add(i)
.write(_mm_mul_pd(
_mm_div_pd(_mm_set1_pd(0.01), distance_Squared),
distance_Reciprocal,
));
{
let mut k = 0;
for i in 0..BODIES_COUNT - 1 {
for j in i + 1..BODIES_COUNT {
let i_mass_magnitude = (*bodies.add(i)).mass * magnitudes.0[k];
let j_mass_magnitude = (*bodies.add(j)).mass * magnitudes.0[k];
for m in 0..3 {
(*bodies.add(i)).velocity[m] -= position_Deltas[m].0[k] * j_mass_magnitude;
(*bodies.add(j)).velocity[m] += position_Deltas[m].0[k] * i_mass_magnitude;
}
k += 1;
}
}
}
for i in 0..BODIES_COUNT {
for m in 0..3 {
(*bodies.add(i)).position[m] += 0.01 * (*bodies.add(i)).velocity[m];
}
}
}
}
fn main() {
unsafe {
offset_Momentum(solar_Bodies.as_mut_ptr());
output_Energy(solar_Bodies.as_mut_ptr());
let c = std::env::args().nth(1).unwrap().parse().unwrap();
for _ in 0..c {
advance(solar_Bodies.as_mut_ptr());
}
output_Energy(solar_Bodies.as_mut_ptr());
}
}