SummationByParts/sbp/src/euler.rs

851 lines
24 KiB
Rust

use super::grid::{Grid, Metrics};
use super::integrate;
use super::operators::{SbpOperator, UpwindOperator};
use super::Float;
use ndarray::azip;
use ndarray::prelude::*;
pub const GAMMA: Float = 1.4;
// A collection of buffers that allows one to efficiently
// move to the next state
#[derive(Debug)]
pub struct System<SBP: SbpOperator> {
sys: (Field, Field),
wb: WorkBuffers,
grid: (Grid, Metrics<SBP>),
}
impl<SBP: SbpOperator> System<SBP> {
pub fn new(x: ndarray::Array2<Float>, y: ndarray::Array2<Float>) -> Self {
let grid = Grid::new(x, y).expect(
"Could not create grid. Different number of elements compared to width*height?",
);
let metrics = grid.metrics().unwrap();
let nx = grid.nx();
let ny = grid.ny();
Self {
sys: (Field::new(ny, nx), Field::new(ny, nx)),
grid: (grid, metrics),
wb: WorkBuffers::new(ny, nx),
}
}
pub fn advance(&mut self, dt: Float) {
let bc = BoundaryCharacteristics {
north: BoundaryCharacteristic::This,
south: BoundaryCharacteristic::This,
east: BoundaryCharacteristic::This,
west: BoundaryCharacteristic::This,
};
let rhs_trad = |k: &mut Field, y: &Field, grid: &Grid, metrics: &Metrics<_>, wb: &mut _| {
let boundaries = boundary_extractor(y, grid, &bc);
RHS_trad(k, y, metrics, &boundaries, wb)
};
integrate::rk4(
rhs_trad,
&self.sys.0,
&mut self.sys.1,
dt,
&self.grid.0,
&self.grid.1,
&mut self.wb.k,
&mut self.wb.tmp,
);
std::mem::swap(&mut self.sys.0, &mut self.sys.1);
}
pub fn vortex(&mut self, t: Float, vortex_parameters: VortexParameters) {
self.sys
.0
.vortex(self.grid.0.x(), self.grid.0.y(), t, vortex_parameters);
}
#[allow(clippy::many_single_char_names)]
pub fn init_with_vortex(&mut self, x0: Float, y0: Float) {
// Should parametrise such that we have radius, drop in pressure at center, etc
let vortex_parameters = VortexParameters {
x0,
y0,
rstar: 1.0,
eps: 3.0,
mach: 0.5,
};
self.sys
.0
.vortex(self.grid.0.x(), self.grid.0.y(), 0.0, vortex_parameters)
}
pub fn field(&self) -> &Field {
&self.sys.0
}
pub fn x(&self) -> ArrayView2<Float> {
self.grid.0.x.view()
}
pub fn y(&self) -> ArrayView2<Float> {
self.grid.0.y.view()
}
}
impl<UO: UpwindOperator> System<UO> {
pub fn advance_upwind(&mut self, dt: Float) {
let bc = BoundaryCharacteristics {
north: BoundaryCharacteristic::This,
south: BoundaryCharacteristic::This,
east: BoundaryCharacteristic::This,
west: BoundaryCharacteristic::This,
};
let rhs_upwind =
|k: &mut Field, y: &Field, grid: &Grid, metrics: &Metrics<_>, wb: &mut _| {
let boundaries = boundary_extractor(y, grid, &bc);
RHS_upwind(k, y, metrics, &boundaries, wb)
};
integrate::rk4(
rhs_upwind,
&self.sys.0,
&mut self.sys.1,
dt,
&self.grid.0,
&self.grid.1,
&mut self.wb.k,
&mut self.wb.tmp,
);
std::mem::swap(&mut self.sys.0, &mut self.sys.1);
}
}
#[derive(Clone, Debug)]
/// A 4 x ny x nx array
pub struct Field(pub(crate) Array3<Float>);
impl std::ops::Deref for Field {
type Target = Array3<Float>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl std::ops::DerefMut for Field {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
impl Field {
pub fn new(ny: usize, nx: usize) -> Self {
let field = Array3::zeros((4, ny, nx));
Self(field)
}
pub fn nx(&self) -> usize {
self.0.shape()[2]
}
pub fn ny(&self) -> usize {
self.0.shape()[1]
}
pub fn rho(&self) -> ArrayView2<Float> {
self.slice(s![0, .., ..])
}
pub fn rhou(&self) -> ArrayView2<Float> {
self.slice(s![1, .., ..])
}
pub fn rhov(&self) -> ArrayView2<Float> {
self.slice(s![2, .., ..])
}
pub fn e(&self) -> ArrayView2<Float> {
self.slice(s![3, .., ..])
}
pub fn rho_mut(&mut self) -> ArrayViewMut2<Float> {
self.slice_mut(s![0, .., ..])
}
pub fn rhou_mut(&mut self) -> ArrayViewMut2<Float> {
self.slice_mut(s![1, .., ..])
}
pub fn rhov_mut(&mut self) -> ArrayViewMut2<Float> {
self.slice_mut(s![2, .., ..])
}
pub fn e_mut(&mut self) -> ArrayViewMut2<Float> {
self.slice_mut(s![3, .., ..])
}
#[allow(unused)]
pub fn components(
&self,
) -> (
ArrayView2<Float>,
ArrayView2<Float>,
ArrayView2<Float>,
ArrayView2<Float>,
) {
(self.rho(), self.rhou(), self.rhov(), self.e())
}
#[allow(unused)]
pub fn components_mut(
&mut self,
) -> (
ArrayViewMut2<Float>,
ArrayViewMut2<Float>,
ArrayViewMut2<Float>,
ArrayViewMut2<Float>,
) {
let mut iter = self.0.outer_iter_mut();
let rho = iter.next().unwrap();
let rhou = iter.next().unwrap();
let rhov = iter.next().unwrap();
let e = iter.next().unwrap();
assert_eq!(iter.next(), None);
(rho, rhou, rhov, e)
}
pub fn north(&self) -> ArrayView2<Float> {
self.slice(s![.., self.ny() - 1, ..])
}
pub fn south(&self) -> ArrayView2<Float> {
self.slice(s![.., 0, ..])
}
pub fn east(&self) -> ArrayView2<Float> {
self.slice(s![.., .., self.nx() - 1])
}
pub fn west(&self) -> ArrayView2<Float> {
self.slice(s![.., .., 0])
}
fn north_mut(&mut self) -> ArrayViewMut2<Float> {
let ny = self.ny();
self.slice_mut(s![.., ny - 1, ..])
}
fn south_mut(&mut self) -> ArrayViewMut2<Float> {
self.slice_mut(s![.., 0, ..])
}
fn east_mut(&mut self) -> ArrayViewMut2<Float> {
let nx = self.nx();
self.slice_mut(s![.., .., nx - 1])
}
fn west_mut(&mut self) -> ArrayViewMut2<Float> {
self.slice_mut(s![.., .., 0])
}
pub fn vortex(
&mut self,
x: ArrayView2<Float>,
y: ArrayView2<Float>,
t: Float,
vortex_param: VortexParameters,
) {
assert_eq!(x.shape(), y.shape());
assert_eq!(x.shape()[1], self.nx());
assert_eq!(x.shape()[0], self.ny());
let (rho, rhou, rhov, e) = self.components_mut();
let n = rho.len();
vortex(
rho.into_shape((n,)).unwrap(),
rhou.into_shape((n,)).unwrap(),
rhov.into_shape((n,)).unwrap(),
e.into_shape((n,)).unwrap(),
x.into_shape((n,)).unwrap(),
y.into_shape((n,)).unwrap(),
t,
vortex_param,
)
}
}
impl Field {
/// sqrt((self-other)^T*H*(self-other))
pub fn h2_err<SBP: SbpOperator>(&self, other: &Self) -> Float {
assert_eq!(self.nx(), other.nx());
assert_eq!(self.ny(), other.ny());
let h = SBP::h();
// Resulting structure should be
// serialized(F0 - F1)^T (Hx kron Hy) serialized(F0 - F1)
//
// We accomplish this by serializing along x as fastest dimension
// Since h is diagonal, it can be iterated with the following iterators
// This chains the h block into the form [h, 1, 1, 1, rev(h)],
// and multiplies with a factor
let itermaker = move |n: usize, factor: Float| {
h.iter()
.copied()
.chain(std::iter::repeat(1.0).take(n - 2 * h.len()))
.chain(h.iter().copied().rev())
.map(move |x| x * factor)
};
let hxiterator = itermaker(self.nx(), 1.0 / (self.nx() - 1) as Float);
// Repeating to get the form
// [[hx0, hx1, ..., hxn], [hx0, hx1, ..., hxn], ..., [hx0, hx1, ..., hxn]]
let hxiterator = hxiterator.into_iter().cycle().take(self.nx() * self.ny());
let hyiterator = itermaker(self.ny(), 1.0 / (self.ny() - 1) as Float);
// Repeating to get the form
// [[hy0, hy0, ..., hy0], [hy1, hy1, ..., hy1], ..., [hym, hym, ..., hym]]
let hyiterator = hyiterator
.into_iter()
.flat_map(|x| std::iter::repeat(x).take(self.nx()));
let diagiterator = hxiterator.into_iter().zip(hyiterator).cycle();
diagiterator
.into_iter()
.zip(self.0.iter())
.zip(other.0.iter())
.map(|(((hx, hy), r0), r1)| (*r0 - *r1).powi(2) * hx * hy)
.sum::<Float>()
.sqrt()
}
}
#[test]
fn h2_diff() {
let mut field0 = Field::new(20, 21);
for f in field0.0.iter_mut() {
*f = 1.0
}
let field1 = Field::new(20, 21);
assert!((field0.h2_err::<super::operators::Upwind4>(&field1).powi(2) - 4.0).abs() < 1e-3);
assert!((field0.h2_err::<super::operators::Upwind9>(&field1).powi(2) - 4.0).abs() < 1e-3);
assert!((field0.h2_err::<super::operators::SBP4>(&field1).powi(2) - 4.0).abs() < 1e-3);
assert!((field0.h2_err::<super::operators::SBP8>(&field1).powi(2) - 4.0).abs() < 1e-3);
}
#[derive(Copy, Clone, Debug)]
pub struct VortexParameters {
pub x0: Float,
pub y0: Float,
pub rstar: Float,
pub eps: Float,
pub mach: Float,
}
pub fn vortex(
rho: ArrayViewMut1<Float>,
rhou: ArrayViewMut1<Float>,
rhov: ArrayViewMut1<Float>,
e: ArrayViewMut1<Float>,
x: ArrayView1<Float>,
y: ArrayView1<Float>,
t: Float,
vortex_param: VortexParameters,
) {
assert_eq!(rho.len(), rhou.len());
assert_eq!(rho.len(), rhov.len());
assert_eq!(rho.len(), e.len());
assert_eq!(rho.len(), x.len());
assert_eq!(rho.len(), y.len());
assert_eq!(x.shape(), y.shape());
let eps = vortex_param.eps;
let m = vortex_param.mach;
let rstar = vortex_param.rstar;
let p_inf = 1.0 / (GAMMA * m * m);
azip!((rho in rho,
rhou in rhou,
rhov in rhov,
e in e,
x in x,
y in y)
{
use crate::consts::PI;
let dx = (x - vortex_param.x0) - t;
let dy = y - vortex_param.y0;
let f = (1.0 - (dx*dx + dy*dy))/(rstar*rstar);
*rho = Float::powf(1.0 - eps*eps*(GAMMA - 1.0)*m*m/(8.0*PI*PI*p_inf*rstar*rstar)*f.exp(), 1.0/(GAMMA - 1.0));
assert!(*rho > 0.0);
let p = Float::powf(*rho, GAMMA)*p_inf;
assert!(p > 0.0);
let u = 1.0 - eps*dy/(2.0*PI*p_inf.sqrt()*rstar*rstar)*(f/2.0).exp();
let v = eps*dx/(2.0*PI*p_inf.sqrt()*rstar*rstar)*(f/2.0).exp();
*rhou = *rho*u;
*rhov = *rho*v;
*e = p/(GAMMA - 1.0) + *rho*(u*u + v*v)/2.0;
});
}
fn pressure(gamma: Float, rho: Float, rhou: Float, rhov: Float, e: Float) -> Float {
(gamma - 1.0) * (e - (rhou * rhou + rhov * rhov) / (2.0 * rho))
}
#[allow(non_snake_case)]
pub(crate) fn RHS_trad<SBP: SbpOperator>(
k: &mut Field,
y: &Field,
metrics: &Metrics<SBP>,
boundaries: &BoundaryTerms,
tmp: &mut (Field, Field, Field, Field, Field, Field),
) {
let ehat = &mut tmp.0;
let fhat = &mut tmp.1;
fluxes((ehat, fhat), y, metrics);
let dE = &mut tmp.2;
let dF = &mut tmp.3;
SBP::diffxi(ehat.rho(), dE.rho_mut());
SBP::diffxi(ehat.rhou(), dE.rhou_mut());
SBP::diffxi(ehat.rhov(), dE.rhov_mut());
SBP::diffxi(ehat.e(), dE.e_mut());
SBP::diffeta(fhat.rho(), dF.rho_mut());
SBP::diffeta(fhat.rhou(), dF.rhou_mut());
SBP::diffeta(fhat.rhov(), dF.rhov_mut());
SBP::diffeta(fhat.e(), dF.e_mut());
azip!((out in &mut k.0,
eflux in &dE.0,
fflux in &dF.0,
detj in &metrics.detj.broadcast((4, y.ny(), y.nx())).unwrap()) {
*out = (-eflux - fflux)/detj
});
SAT_characteristics(k, y, metrics, boundaries);
}
#[allow(non_snake_case)]
pub fn RHS_upwind<UO: UpwindOperator>(
k: &mut Field,
y: &Field,
metrics: &Metrics<UO>,
boundaries: &BoundaryTerms,
tmp: &mut (Field, Field, Field, Field, Field, Field),
) {
let ehat = &mut tmp.0;
let fhat = &mut tmp.1;
fluxes((ehat, fhat), y, metrics);
let dE = &mut tmp.2;
let dF = &mut tmp.3;
UO::diffxi(ehat.rho(), dE.rho_mut());
UO::diffxi(ehat.rhou(), dE.rhou_mut());
UO::diffxi(ehat.rhov(), dE.rhov_mut());
UO::diffxi(ehat.e(), dE.e_mut());
UO::diffeta(fhat.rho(), dF.rho_mut());
UO::diffeta(fhat.rhou(), dF.rhou_mut());
UO::diffeta(fhat.rhov(), dF.rhov_mut());
UO::diffeta(fhat.e(), dF.e_mut());
let ad_xi = &mut tmp.4;
let ad_eta = &mut tmp.5;
upwind_dissipation((ad_xi, ad_eta), y, metrics, (&mut tmp.0, &mut tmp.1));
azip!((out in &mut k.0,
eflux in &dE.0,
fflux in &dF.0,
ad_xi in &ad_xi.0,
ad_eta in &ad_eta.0,
detj in &metrics.detj.broadcast((4, y.ny(), y.nx())).unwrap()) {
*out = (-eflux - fflux + ad_xi + ad_eta)/detj
});
SAT_characteristics(k, y, metrics, boundaries);
}
#[allow(clippy::many_single_char_names)]
fn upwind_dissipation<UO: UpwindOperator>(
k: (&mut Field, &mut Field),
y: &Field,
metrics: &Metrics<UO>,
tmp: (&mut Field, &mut Field),
) {
let n = y.nx() * y.ny();
let yview = y.view().into_shape((4, n)).unwrap();
let mut tmp0 = tmp.0.view_mut().into_shape((4, n)).unwrap();
let mut tmp1 = tmp.1.view_mut().into_shape((4, n)).unwrap();
for (
((((((y, mut tmp0), mut tmp1), detj), detj_dxi_dx), detj_dxi_dy), detj_deta_dx),
detj_deta_dy,
) in yview
.axis_iter(ndarray::Axis(1))
.zip(tmp0.axis_iter_mut(ndarray::Axis(1)))
.zip(tmp1.axis_iter_mut(ndarray::Axis(1)))
.zip(metrics.detj.iter())
.zip(metrics.detj_dxi_dx.iter())
.zip(metrics.detj_dxi_dy.iter())
.zip(metrics.detj_deta_dx.iter())
.zip(metrics.detj_deta_dy.iter())
{
let rho = y[0];
assert!(rho > 0.0);
let rhou = y[1];
let rhov = y[2];
let e = y[3];
let u = rhou / rho;
let v = rhov / rho;
let uhat = detj_dxi_dx / detj * u + detj_dxi_dy / detj * v;
let vhat = detj_deta_dx / detj * u + detj_deta_dy / detj * v;
let p = pressure(GAMMA, rho, rhou, rhov, e);
assert!(p > 0.0);
let c = (GAMMA * p / rho).sqrt();
let alpha_u = uhat.abs() + c;
let alpha_v = vhat.abs() + c;
tmp0[0] = alpha_u * rho * detj;
tmp1[0] = alpha_v * rho * detj;
tmp0[1] = alpha_u * rhou * detj;
tmp1[1] = alpha_v * rhou * detj;
tmp0[2] = alpha_u * rhov * detj;
tmp1[2] = alpha_v * rhov * detj;
tmp0[3] = alpha_u * e * detj;
tmp1[3] = alpha_v * e * detj;
}
UO::dissxi(tmp.0.rho(), k.0.rho_mut());
UO::dissxi(tmp.0.rhou(), k.0.rhou_mut());
UO::dissxi(tmp.0.rhov(), k.0.rhov_mut());
UO::dissxi(tmp.0.e(), k.0.e_mut());
UO::disseta(tmp.1.rho(), k.1.rho_mut());
UO::disseta(tmp.1.rhou(), k.1.rhou_mut());
UO::disseta(tmp.1.rhov(), k.1.rhov_mut());
UO::disseta(tmp.1.e(), k.1.e_mut());
}
fn fluxes<SBP: SbpOperator>(k: (&mut Field, &mut Field), y: &Field, metrics: &Metrics<SBP>) {
let j_dxi_dx = metrics.detj_dxi_dx.view();
let j_dxi_dy = metrics.detj_dxi_dy.view();
let j_deta_dx = metrics.detj_deta_dx.view();
let j_deta_dy = metrics.detj_deta_dy.view();
let rho = y.rho();
let rhou = y.rhou();
let rhov = y.rhov();
let e = y.e();
for j in 0..y.ny() {
for i in 0..y.nx() {
let rho = rho[(j, i)];
assert!(rho > 0.0);
let rhou = rhou[(j, i)];
let rhov = rhov[(j, i)];
let e = e[(j, i)];
let p = pressure(GAMMA, rho, rhou, rhov, e);
assert!(p > 0.0);
let ef = [
rhou,
rhou * rhou / rho + p,
rhou * rhov / rho,
rhou * (e + p) / rho,
];
let ff = [
rhov,
rhou * rhov / rho,
rhov * rhov / rho + p,
rhov * (e + p) / rho,
];
for comp in 0..4 {
let eflux = j_dxi_dx[(j, i)] * ef[comp] + j_dxi_dy[(j, i)] * ff[comp];
let fflux = j_deta_dx[(j, i)] * ef[comp] + j_deta_dy[(j, i)] * ff[comp];
k.0[(comp, j, i)] = eflux;
k.1[(comp, j, i)] = fflux;
}
}
}
}
#[derive(Clone, Debug)]
pub struct BoundaryTerms<'a> {
pub north: ArrayView2<'a, Float>,
pub south: ArrayView2<'a, Float>,
pub east: ArrayView2<'a, Float>,
pub west: ArrayView2<'a, Float>,
}
#[derive(Clone, Debug)]
pub enum BoundaryCharacteristic {
This,
Grid(usize),
Vortex(VortexParameters),
// Vortices(Vec<VortexParameters>),
}
#[derive(Clone, Debug)]
pub struct BoundaryCharacteristics {
pub north: BoundaryCharacteristic,
pub south: BoundaryCharacteristic,
pub east: BoundaryCharacteristic,
pub west: BoundaryCharacteristic,
}
fn boundary_extractor<'a>(
field: &'a Field,
_grid: &Grid,
bc: &BoundaryCharacteristics,
) -> BoundaryTerms<'a> {
BoundaryTerms {
north: match bc.north {
BoundaryCharacteristic::This => field.south(),
BoundaryCharacteristic::Vortex(_params) => todo!(),
BoundaryCharacteristic::Grid(_) => panic!("Only working on self grid"),
},
south: match bc.south {
BoundaryCharacteristic::This => field.north(),
BoundaryCharacteristic::Vortex(_params) => todo!(),
BoundaryCharacteristic::Grid(_) => panic!("Only working on self grid"),
},
west: match bc.west {
BoundaryCharacteristic::This => field.east(),
BoundaryCharacteristic::Vortex(_params) => todo!(),
BoundaryCharacteristic::Grid(_) => panic!("Only working on self grid"),
},
east: match bc.east {
BoundaryCharacteristic::This => field.west(),
BoundaryCharacteristic::Vortex(_params) => todo!(),
BoundaryCharacteristic::Grid(_) => panic!("Only working on self grid"),
},
}
}
#[allow(non_snake_case)]
/// Boundary conditions (SAT)
fn SAT_characteristics<SBP: SbpOperator>(
k: &mut Field,
y: &Field,
metrics: &Metrics<SBP>,
boundaries: &BoundaryTerms,
) {
// North boundary
{
let hi = (k.ny() - 1) as Float * SBP::h()[0];
let sign = -1.0;
let tau = 1.0;
let slice = s![y.ny() - 1, ..];
SAT_characteristic(
k.north_mut(),
y.north(),
boundaries.north,
hi,
sign,
tau,
metrics.detj.slice(slice),
metrics.detj_deta_dx.slice(slice),
metrics.detj_deta_dy.slice(slice),
);
}
// South boundary
{
let hi = (k.ny() - 1) as Float * SBP::h()[0];
let sign = 1.0;
let tau = -1.0;
let slice = s![0, ..];
SAT_characteristic(
k.south_mut(),
y.south(),
boundaries.south,
hi,
sign,
tau,
metrics.detj.slice(slice),
metrics.detj_deta_dx.slice(slice),
metrics.detj_deta_dy.slice(slice),
);
}
// West Boundary
{
let hi = (k.nx() - 1) as Float * SBP::h()[0];
let sign = 1.0;
let tau = -1.0;
let slice = s![.., 0];
SAT_characteristic(
k.west_mut(),
y.west(),
boundaries.west,
hi,
sign,
tau,
metrics.detj.slice(slice),
metrics.detj_dxi_dx.slice(slice),
metrics.detj_dxi_dy.slice(slice),
);
}
// East Boundary
{
let hi = (k.nx() - 1) as Float * SBP::h()[0];
let sign = -1.0;
let tau = 1.0;
let slice = s![.., y.nx() - 1];
SAT_characteristic(
k.east_mut(),
y.east(),
boundaries.east,
hi,
sign,
tau,
metrics.detj.slice(slice),
metrics.detj_dxi_dx.slice(slice),
metrics.detj_dxi_dy.slice(slice),
);
}
}
#[allow(non_snake_case)]
#[allow(clippy::many_single_char_names)]
#[allow(clippy::too_many_arguments)]
/// Boundary conditions (SAT)
fn SAT_characteristic(
mut k: ArrayViewMut2<Float>,
y: ArrayView2<Float>,
z: ArrayView2<Float>, // Size 4 x n (all components in line)
hi: Float,
sign: Float,
tau: Float,
detj: ArrayView1<Float>,
detj_d_dx: ArrayView1<Float>,
detj_d_dy: ArrayView1<Float>,
) {
assert_eq!(detj.shape(), detj_d_dx.shape());
assert_eq!(detj.shape(), detj_d_dy.shape());
assert_eq!(y.shape(), z.shape());
assert_eq!(y.shape()[0], 4);
assert_eq!(y.shape()[1], detj.shape()[0]);
for (((((mut k, y), z), detj), detj_d_dx), detj_d_dy) in k
.axis_iter_mut(ndarray::Axis(1))
.zip(y.axis_iter(ndarray::Axis(1)))
.zip(z.axis_iter(ndarray::Axis(1)))
.zip(detj.iter())
.zip(detj_d_dx.iter())
.zip(detj_d_dy.iter())
{
let rho = y[0];
let rhou = y[1];
let rhov = y[2];
let e = y[3];
let kx_ = detj_d_dx / detj;
let ky_ = detj_d_dy / detj;
let (kx, ky) = {
let r = Float::hypot(kx_, ky_);
(kx_ / r, ky_ / r)
};
let u = rhou / rho;
let v = rhov / rho;
let theta = kx * u + ky * v;
let p = pressure(GAMMA, rho, rhou, rhov, e);
let c = (GAMMA * p / rho).sqrt();
let phi2 = (GAMMA - 1.0) * (u * u + v * v) / 2.0;
let phi2_c2 = (phi2 + c * c) / (GAMMA - 1.0);
let T = [
[1.0, 0.0, 1.0, 1.0],
[u, ky, u + kx * c, u - kx * c],
[v, -kx, v + ky * c, v - ky * c],
[
phi2 / (GAMMA - 1.0),
ky * u - kx * v,
phi2_c2 + c * theta,
phi2_c2 - c * theta,
],
];
let U = kx_ * u + ky_ * v;
let L = [
U,
U,
U + c * Float::hypot(kx_, ky_),
U - c * Float::hypot(kx_, ky_),
];
let beta = 1.0 / (2.0 * c * c);
let TI = [
[
1.0 - phi2 / (c * c),
(GAMMA - 1.0) * u / (c * c),
(GAMMA - 1.0) * v / (c * c),
-(GAMMA - 1.0) / (c * c),
],
[-(ky * u - kx * v), ky, -kx, 0.0],
[
beta * (phi2 - c * theta),
beta * (kx * c - (GAMMA - 1.0) * u),
beta * (ky * c - (GAMMA - 1.0) * v),
beta * (GAMMA - 1.0),
],
[
beta * (phi2 + c * theta),
-beta * (kx * c + (GAMMA - 1.0) * u),
-beta * (ky * c + (GAMMA - 1.0) * v),
beta * (GAMMA - 1.0),
],
];
let res = [rho - z[0], rhou - z[1], rhov - z[2], e - z[3]];
let mut TIres = [0.0; 4];
#[allow(clippy::needless_range_loop)]
for row in 0..4 {
for col in 0..4 {
TIres[row] += TI[row][col] * res[col];
}
}
// L + sign(abs(L)) * TIres
let mut LTIres = [0.0; 4];
for row in 0..4 {
LTIres[row] = (L[row] + sign * L[row].abs()) * TIres[row];
}
// T*LTIres
let mut TLTIres = [0.0; 4];
#[allow(clippy::needless_range_loop)]
for row in 0..4 {
for col in 0..4 {
TLTIres[row] += T[row][col] * LTIres[col];
}
}
for comp in 0..4 {
k[comp] += hi * tau * TLTIres[comp];
}
}
}
#[derive(Debug)]
pub struct WorkBuffers {
k: [Field; 4],
tmp: (Field, Field, Field, Field, Field, Field),
}
impl WorkBuffers {
pub fn new(nx: usize, ny: usize) -> Self {
let arr3 = Field::new(nx, ny);
Self {
k: [arr3.clone(), arr3.clone(), arr3.clone(), arr3.clone()],
tmp: (
arr3.clone(),
arr3.clone(),
arr3.clone(),
arr3.clone(),
arr3.clone(),
arr3,
),
}
}
}