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solve 2D maxwell

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Magnus Ulimoen
2019-08-09 21:00:15 +02:00
parent 6816d6bd43
commit 43f1088d66
2 changed files with 73 additions and 55 deletions
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78
src/lib.rs
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@@ -2,7 +2,7 @@ use ndarray::{Array2, Zip};
use wasm_bindgen::prelude::*;
mod operators;
use operators::diffx_periodic;
use operators::{diffx_periodic, diffy_periodic};
#[cfg(feature = "wee_alloc")]
#[global_allocator]
@@ -11,7 +11,7 @@ static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
#[wasm_bindgen]
pub struct Universe {
ex: Array2<f32>,
// e_y: Array2<f32>,
ey: Array2<f32>,
hz: Array2<f32>,
}
@@ -36,37 +36,21 @@ fn exponential(x: f32, y: f32, _t: f32) -> f32 {
1.0 / (2.0 * f32::consts::PI * sigma * sigma) * (-(x * x + y * y) / (2.0 * sigma * sigma)).exp()
}
fn gaussian(x: f32, y: f32, t: f32) -> f32 {
use std::f32;
let x = x - 0.5;
let y = y - 0.5;
let sigma = 0.05;
1.0 / (2.0 * f32::consts::PI * sigma * sigma)
* (-(x + y - t) * (x + y - t) / (2.0 * sigma * sigma)).exp()
}
#[wasm_bindgen]
impl Universe {
pub fn new(width: u32, height: u32) -> Self {
let field = Array2::zeros((height as usize, width as usize));
let ex = field.clone();
// let e_y = field.clone();
let hz = field.clone();
let ey = field.clone();
let hz = field;
Universe {
ex,
// e_y,
hz,
}
Universe { ex, ey, hz }
}
pub fn set_initial(&mut self, t: f32, selected_function: &str) {
let func = match selected_function {
"sin+cos" => sin_plus_cos,
"exp" => exponential,
"gauss" => gaussian,
_ => |_x: f32, _y: f32, _t: f32| 0.0,
};
let nx = self.ex.shape()[1];
@@ -77,9 +61,9 @@ impl Universe {
// due to periodic conditions [0, 1)
let x = i as f32 / nx as f32;
let y = j as f32 / ny as f32;
self.ex[(j, i)] = func(x, y, t);
self.hz[(j, i)] = -func(x, y, t);
// self.e_y[(j as usize, i as usize)] = func(x, y, t);
self.ex[(j, i)] = 0.0;
self.ey[(j, i)] = 0.0;
self.hz[(j, i)] = func(x, y, t);
}
}
}
@@ -97,19 +81,23 @@ impl Universe {
// y = y0 + c*kn
y.0.assign(&self.ex);
y.1.assign(&self.hz);
y.2.assign(&self.ey);
match i {
0 => {}
1 => {
y.0.scaled_add(1.0 / 2.0 * dt, &k[i - 1].0);
y.1.scaled_add(1.0 / 2.0 * dt, &k[i - 1].1);
y.2.scaled_add(1.0 / 2.0 * dt, &k[i - 1].2);
}
2 => {
y.0.scaled_add(1.0 / 2.0 * dt, &k[i - 1].0);
y.1.scaled_add(1.0 / 2.0 * dt, &k[i - 1].1);
y.2.scaled_add(1.0 / 2.0 * dt, &k[i - 1].2);
}
3 => {
y.0.scaled_add(dt, &k[i - 1].0);
y.1.scaled_add(dt, &k[i - 1].1);
y.2.scaled_add(dt, &k[i - 1].2);
}
_ => {
unreachable!();
@@ -117,10 +105,19 @@ impl Universe {
};
k[i].0.fill(0.0);
k[i].1.fill(0.0);
// ex = hz_y
diffy_periodic(y.1.view(), k[i].0.view_mut());
diffx_periodic(y.0.view(), k[i].1.view_mut());
diffx_periodic(y.1.view(), k[i].0.view_mut());
// ey = -hz_x
k[i].2.fill(0.0);
diffx_periodic(y.1.view(), k[i].2.view_mut());
k[i].2.mapv_inplace(|v| -v);
// hz = -ey_x + ex_y
k[i].1.fill(0.0);
diffx_periodic(y.2.view(), k[i].1.view_mut());
k[i].1.mapv_inplace(|v| -v);
diffy_periodic(y.0.view(), k[i].1.view_mut());
}
Zip::from(&mut fut.ex)
@@ -141,12 +138,25 @@ impl Universe {
.apply(|y1, &y0, &k1, &k2, &k3, &k4| {
*y1 = y0 + dt / 6.0 * (k1 + 2.0 * k2 + 2.0 * k3 + k4)
});
Zip::from(&mut fut.ey)
.and(&self.ey)
.and(&k[0].2)
.and(&k[1].2)
.and(&k[2].2)
.and(&k[3].2)
.apply(|y1, &y0, &k1, &k2, &k3, &k4| {
*y1 = y0 + dt / 6.0 * (k1 + 2.0 * k2 + 2.0 * k3 + k4)
});
}
pub fn get_ex_ptr(&mut self) -> *mut u8 {
self.ex.as_mut_ptr() as *mut u8
}
pub fn get_ey_ptr(&mut self) -> *mut u8 {
self.ey.as_mut_ptr() as *mut u8
}
pub fn get_hz_ptr(&mut self) -> *mut u8 {
self.hz.as_mut_ptr() as *mut u8
}
@@ -154,8 +164,8 @@ impl Universe {
#[wasm_bindgen]
pub struct WorkBuffers {
y: (Array2<f32>, Array2<f32>),
buf: [(Array2<f32>, Array2<f32>); 4],
y: (Array2<f32>, Array2<f32>, Array2<f32>),
buf: [(Array2<f32>, Array2<f32>, Array2<f32>); 4],
}
#[wasm_bindgen]
@@ -163,12 +173,12 @@ impl WorkBuffers {
pub fn new(nx: usize, ny: usize) -> Self {
let arr = Array2::zeros((ny, nx));
Self {
y: (arr.clone(), arr.clone()),
y: (arr.clone(), arr.clone(), arr.clone()),
buf: [
(arr.clone(), arr.clone()),
(arr.clone(), arr.clone()),
(arr.clone(), arr.clone()),
(arr.clone(), arr),
(arr.clone(), arr.clone(), arr.clone()),
(arr.clone(), arr.clone(), arr.clone()),
(arr.clone(), arr.clone(), arr.clone()),
(arr.clone(), arr.clone(), arr),
],
}
}