69 lines
2.0 KiB
Rust
69 lines
2.0 KiB
Rust
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use ndarray::Array1;
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use plotters::prelude::*;
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use sbp::{
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integrate::{integrate, Rk4},
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operators::{SbpOperator1d2, SBP4},
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Float,
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};
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fn main() {
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let drawing_area = BitMapBackend::gif("result.gif", (300, 300), 100)
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.unwrap()
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.into_drawing_area();
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let mut chart = ChartBuilder::on(&drawing_area)
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.x_label_area_size(40)
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.y_label_area_size(40)
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.build_cartesian_2d(0.0..1.0, -1.0..2.0)
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.unwrap();
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let nx: usize = 101;
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let dt = 0.2 / nx.pow(2) as Float / 3.0;
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let x = Array1::from_shape_fn((nx,), |i| i as Float / (nx - 1) as Float);
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let v0 = x.map(|&x| 0.0 * x * x * x * x);
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let op = SBP4;
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let mut k = [v0.clone(), v0.clone(), v0.clone(), v0.clone()];
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let rhs = move |fut: &mut Array1<Float>, prev: &Array1<Float>, _t: Float| {
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fut.fill(0.0);
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op.diff2(prev.view(), fut.view_mut());
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let h = 1.0 / (nx - 1) as Float;
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let tau = (1.0, -1.0);
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let v0 = 1.0;
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let vn = -1.0;
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let d1 = op.d1();
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for (d, fut) in d1.iter().zip(fut.iter_mut()) {
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*fut += tau.0 / (h * h) * d * (prev[0] - v0);
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}
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for (d, fut) in d1.iter().zip(fut.iter_mut().rev().take(d1.len()).rev()) {
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*fut += tau.1 / (h * h) * d * (prev[nx - 1] - vn);
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}
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};
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let mut v1 = v0.clone();
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let mut v2 = v0;
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for i in 0..90 {
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if i % 3 == 0 {
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drawing_area.fill(&WHITE).unwrap();
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chart
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.configure_mesh()
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.x_desc("x")
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.y_desc("y")
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.draw()
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.unwrap();
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chart
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.draw_series(LineSeries::new(
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x.iter().zip(v1.iter()).map(|(&x, &y)| (x, y)),
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&BLACK,
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))
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.unwrap();
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drawing_area.present().unwrap();
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}
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integrate::<Rk4, _, _, _>(rhs, &v1, &mut v2, &mut 0.0, dt, &mut k);
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std::mem::swap(&mut v1, &mut v2);
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}
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}
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