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Move integrate to separate crate

This commit is contained in:
Magnus Ulimoen 2021-03-22 17:49:35 +01:00
parent be1330ec02
commit 7aadda3de9
16 changed files with 187 additions and 118 deletions
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1
Cargo.toml
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@ -9,6 +9,7 @@ members = [
"gridgeneration", "gridgeneration",
"heat-equation", "heat-equation",
"utils/float", "utils/float",
"utils/integrate",
"utils/constmatrix", "utils/constmatrix",
] ]

1
euler/Cargo.toml
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@ -15,6 +15,7 @@ ndarray = "0.14.0"
sbp = { path = "../sbp" } sbp = { path = "../sbp" }
arrayvec = "0.5.1" arrayvec = "0.5.1"
serde = { version = "1.0.115", default-features = false, optional = true, features = ["derive"] } serde = { version = "1.0.115", default-features = false, optional = true, features = ["derive"] }
integrate = { path = "../utils/integrate" }
[dev-dependencies] [dev-dependencies]
criterion = "0.3.2" criterion = "0.3.2"

53
euler/src/lib.rs
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@ -2,7 +2,6 @@ pub use arrayvec::ArrayVec;
use ndarray::azip; use ndarray::azip;
use ndarray::prelude::*; use ndarray::prelude::*;
use sbp::grid::{Grid, Metrics}; use sbp::grid::{Grid, Metrics};
use sbp::integrate;
use sbp::operators::{InterpolationOperator, SbpOperator2d, UpwindOperator2d}; use sbp::operators::{InterpolationOperator, SbpOperator2d, UpwindOperator2d};
use sbp::utils::Direction; use sbp::utils::Direction;
use sbp::Float; use sbp::Float;
@ -57,7 +56,7 @@ impl<SBP: SbpOperator2d> System<SBP> {
let boundaries = boundary_extractor(y, grid, &bc); let boundaries = boundary_extractor(y, grid, &bc);
RHS_trad(op, k, y, metrics, &boundaries, wb) RHS_trad(op, k, y, metrics, &boundaries, wb)
}; };
integrate::integrate::<integrate::Rk4, _, _, _>( integrate::integrate::<integrate::Rk4, Field, _>(
rhs_trad, rhs_trad,
&self.sys.0, &self.sys.0,
&mut self.sys.1, &mut self.sys.1,
@ -131,7 +130,7 @@ impl<UO: UpwindOperator2d + SbpOperator2d> System<UO> {
let boundaries = boundary_extractor(y, grid, &bc); let boundaries = boundary_extractor(y, grid, &bc);
RHS_upwind(op, k, y, metrics, &boundaries, wb) RHS_upwind(op, k, y, metrics, &boundaries, wb)
}; };
integrate::integrate::<integrate::Rk4, _, _, _>( integrate::integrate::<integrate::Rk4, Field, _>(
rhs_upwind, rhs_upwind,
&self.sys.0, &self.sys.0,
&mut self.sys.1, &mut self.sys.1,
@ -159,7 +158,7 @@ impl<UO: UpwindOperator2d + SbpOperator2d> System<UO> {
let mut time = 0.0; let mut time = 0.0;
let mut sys2 = self.sys.0.clone(); let mut sys2 = self.sys.0.clone();
while time < dt { while time < dt {
integrate::integrate_embedded_rk::<integrate::BogackiShampine, _, _, _>( integrate::integrate_embedded_rk::<integrate::BogackiShampine, Field, _>(
&mut rhs_upwind, &mut rhs_upwind,
&self.sys.0, &self.sys.0,
&mut self.sys.1, &mut self.sys.1,
@ -184,27 +183,15 @@ impl<UO: UpwindOperator2d + SbpOperator2d> System<UO> {
/// A 4 x ny x nx array /// A 4 x ny x nx array
pub struct Field(pub(crate) Array3<Float>); pub struct Field(pub(crate) Array3<Float>);
impl std::ops::Deref for Field { impl integrate::Integrable for Field {
type Target = Array3<Float>; type State = Field;
fn deref(&self) -> &Self::Target { type Diff = Field;
&self.0
}
}
impl std::ops::DerefMut for Field { fn assign(s: &mut Self::State, o: &Self::State) {
fn deref_mut(&mut self) -> &mut Self::Target { s.0.assign(&o.0);
&mut self.0
} }
} fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
s.0.scaled_add(scale, &o.0);
impl<'a> std::convert::From<&'a Field> for ArrayView3<'a, Float> {
fn from(f: &'a Field) -> Self {
f.0.view()
}
}
impl<'a> std::convert::From<&'a mut Field> for ArrayViewMut3<'a, Float> {
fn from(f: &'a mut Field) -> Self {
f.0.view_mut()
} }
} }
@ -222,6 +209,20 @@ impl Field {
self.0.shape()[1] self.0.shape()[1]
} }
pub(crate) fn slice<Do: Dimension>(
&self,
info: &ndarray::SliceInfo<[ndarray::SliceOrIndex; 3], Do>,
) -> ArrayView<Float, Do> {
self.0.slice(info)
}
pub(crate) fn slice_mut<Do: Dimension>(
&mut self,
info: &ndarray::SliceInfo<[ndarray::SliceOrIndex; 3], Do>,
) -> ArrayViewMut<Float, Do> {
self.0.slice_mut(info)
}
pub fn rho(&self) -> ArrayView2<Float> { pub fn rho(&self) -> ArrayView2<Float> {
self.slice(s![0, .., ..]) self.slice(s![0, .., ..])
} }
@ -613,9 +614,9 @@ fn upwind_dissipation(
tmp: (&mut Field, &mut Field), tmp: (&mut Field, &mut Field),
) { ) {
let n = y.nx() * y.ny(); let n = y.nx() * y.ny();
let yview = y.view().into_shape((4, n)).unwrap(); let yview = y.0.view().into_shape((4, n)).unwrap();
let mut tmp0 = tmp.0.view_mut().into_shape((4, n)).unwrap(); let mut tmp0 = tmp.0 .0.view_mut().into_shape((4, n)).unwrap();
let mut tmp1 = tmp.1.view_mut().into_shape((4, n)).unwrap(); let mut tmp1 = tmp.1 .0.view_mut().into_shape((4, n)).unwrap();
for ((((((y, mut tmp0), mut tmp1), detj_dxi_dx), detj_dxi_dy), detj_deta_dx), detj_deta_dy) in for ((((((y, mut tmp0), mut tmp1), detj_dxi_dx), detj_dxi_dy), detj_deta_dx), detj_deta_dy) in
yview yview

1
heat-equation/Cargo.toml
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@ -10,6 +10,7 @@ sbp = { path = "../sbp", features = ["sparse"] }
ndarray = "0.14.0" ndarray = "0.14.0"
plotters = { version = "0.3.0", default-features = false, features = ["bitmap_gif", "bitmap_backend", "line_series"] } plotters = { version = "0.3.0", default-features = false, features = ["bitmap_gif", "bitmap_backend", "line_series"] }
sprs = { version = "0.10.0", default-features = false } sprs = { version = "0.10.0", default-features = false }
integrate = { path = "../utils/integrate" }
[dev-dependencies] [dev-dependencies]
arpack = { git = "https://github.com/mulimoen/arpack-rs", branch = "main" } arpack = { git = "https://github.com/mulimoen/arpack-rs", branch = "main" }

21
heat-equation/src/main.rs
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@ -1,11 +1,24 @@
use integrate::{integrate, Rk4};
use ndarray::{Array1, ArrayView1}; use ndarray::{Array1, ArrayView1};
use plotters::prelude::*; use plotters::prelude::*;
use sbp::{ use sbp::{
integrate::{integrate, Rk4},
operators::{SbpOperator1d, SbpOperator1d2, SBP4}, operators::{SbpOperator1d, SbpOperator1d2, SBP4},
Float, Float,
}; };
struct Field(Array1<Float>);
impl integrate::Integrable for Field {
type State = Array1<Float>;
type Diff = Array1<Float>;
fn assign(s: &mut Self::State, o: &Self::State) {
s.assign(o)
}
fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
s.scaled_add(scale, o)
}
}
fn main() { fn main() {
let nx: usize = 101; let nx: usize = 101;
let x = Array1::from_shape_fn((nx,), |i| i as Float / (nx - 1) as Float); let x = Array1::from_shape_fn((nx,), |i| i as Float / (nx - 1) as Float);
@ -76,7 +89,7 @@ fn dual_dirichlet(v: ArrayView1<Float>, v0: Float, vn: Float) {
.unwrap(); .unwrap();
drawing_area.present().unwrap(); drawing_area.present().unwrap();
} }
integrate::<Rk4, _, _, _>(rhs, &v1, &mut v2, &mut 0.0, dt, &mut k); integrate::<Rk4, Field, _>(rhs, &v1, &mut v2, &mut 0.0, dt, &mut k);
std::mem::swap(&mut v1, &mut v2); std::mem::swap(&mut v1, &mut v2);
} }
} }
@ -143,7 +156,7 @@ fn neumann_dirichlet(v: ArrayView1<Float>, v0: Float, vn: Float) {
.unwrap(); .unwrap();
drawing_area.present().unwrap(); drawing_area.present().unwrap();
} }
integrate::<Rk4, _, _, _>(rhs, &v1, &mut v2, &mut 0.0, dt, &mut k); integrate::<Rk4, Field, _>(rhs, &v1, &mut v2, &mut 0.0, dt, &mut k);
std::mem::swap(&mut v1, &mut v2); std::mem::swap(&mut v1, &mut v2);
} }
} }
@ -231,7 +244,7 @@ fn dual_dirichlet_sparse(v: ArrayView1<Float>, v0: Float, vn: Float) {
.unwrap(); .unwrap();
drawing_area.present().unwrap(); drawing_area.present().unwrap();
} }
integrate::<Rk4, _, _, _>(rhs, &v1, &mut v2, &mut 0.0, dt, &mut k); integrate::<Rk4, Field, _>(rhs, &v1, &mut v2, &mut 0.0, dt, &mut k);
std::mem::swap(&mut v1, &mut v2); std::mem::swap(&mut v1, &mut v2);
} }
} }

1
maxwell/Cargo.toml
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@ -11,6 +11,7 @@ sparse = ["sbp/sparse", "sprs"]
ndarray = "0.14.0" ndarray = "0.14.0"
sbp = { path = "../sbp" } sbp = { path = "../sbp" }
sprs = { version = "0.10.0", optional = true, default-features = false } sprs = { version = "0.10.0", optional = true, default-features = false }
integrate = { path = "../utils/integrate" }
[dev-dependencies] [dev-dependencies]
criterion = "0.3.2" criterion = "0.3.2"

59
maxwell/src/lib.rs
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@ -1,7 +1,6 @@
use ndarray::azip; use ndarray::azip;
use ndarray::prelude::*; use ndarray::prelude::*;
use sbp::grid::{Grid, Metrics}; use sbp::grid::{Grid, Metrics};
use sbp::integrate;
use sbp::operators::{SbpOperator2d, UpwindOperator2d}; use sbp::operators::{SbpOperator2d, UpwindOperator2d};
use sbp::Float; use sbp::Float;
@ -11,27 +10,15 @@ pub mod sparse;
#[derive(Clone, Debug)] #[derive(Clone, Debug)]
pub struct Field(pub(crate) Array3<Float>); pub struct Field(pub(crate) Array3<Float>);
impl std::ops::Deref for Field { impl integrate::Integrable for Field {
type Target = Array3<Float>; type State = Field;
fn deref(&self) -> &Self::Target { type Diff = Field;
&self.0
}
}
impl std::ops::DerefMut for Field { fn assign(s: &mut Self::State, o: &Self::State) {
fn deref_mut(&mut self) -> &mut Self::Target { s.0.assign(&o.0);
&mut self.0
} }
} fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
s.0.scaled_add(scale, &o.0);
impl<'a> std::convert::From<&'a Field> for ArrayView3<'a, Float> {
fn from(f: &'a Field) -> Self {
f.0.view()
}
}
impl<'a> std::convert::From<&'a mut Field> for ArrayViewMut3<'a, Float> {
fn from(f: &'a mut Field) -> Self {
f.0.view_mut()
} }
} }
@ -49,6 +36,20 @@ impl Field {
self.0.shape()[1] self.0.shape()[1]
} }
pub(crate) fn slice<Do: Dimension>(
&self,
info: &ndarray::SliceInfo<[ndarray::SliceOrIndex; 3], Do>,
) -> ArrayView<Float, Do> {
self.0.slice(info)
}
pub(crate) fn slice_mut<Do: Dimension>(
&mut self,
info: &ndarray::SliceInfo<[ndarray::SliceOrIndex; 3], Do>,
) -> ArrayViewMut<Float, Do> {
self.0.slice_mut(info)
}
pub fn ex(&self) -> ArrayView2<Float> { pub fn ex(&self) -> ArrayView2<Float> {
self.slice(s![0, .., ..]) self.slice(s![0, .., ..])
} }
@ -147,7 +148,7 @@ impl<SBP: SbpOperator2d> System<SBP> {
RHS(op, fut, prev, grid, metrics, wb); RHS(op, fut, prev, grid, metrics, wb);
}; };
let mut _time = 0.0; let mut _time = 0.0;
integrate::integrate::<integrate::Rk4, _, _, _>( integrate::integrate::<integrate::Rk4, Field, _>(
rhs_adaptor, rhs_adaptor,
&self.sys.0, &self.sys.0,
&mut self.sys.1, &mut self.sys.1,
@ -162,15 +163,15 @@ impl<SBP: SbpOperator2d> System<SBP> {
let rhs = self.rhs.view(); let rhs = self.rhs.view();
//let lhs = self.explicit.view(); //let lhs = self.explicit.view();
let rhs_f = |next: &mut Field, now: &Field, _t: Float| { let rhs_f = |next: &mut Field, now: &Field, _t: Float| {
next.fill(0.0); next.0.fill(0.0);
sprs::prod::mul_acc_mat_vec_csr( sprs::prod::mul_acc_mat_vec_csr(
rhs, rhs,
now.as_slice().unwrap(), now.0.as_slice().unwrap(),
next.as_slice_mut().unwrap(), next.0.as_slice_mut().unwrap(),
); );
// sprs::lingalg::dsolve(..) // sprs::lingalg::dsolve(..)
}; };
sbp::integrate::integrate::<sbp::integrate::Rk4, _, _, _>( integrate::integrate::<integrate::Rk4, Field, _>(
rhs_f, rhs_f,
&self.sys.0, &self.sys.0,
&mut self.sys.1, &mut self.sys.1,
@ -188,9 +189,9 @@ impl<SBP: SbpOperator2d> System<SBP> {
sbp::utils::jacobi_method( sbp::utils::jacobi_method(
lhs, lhs,
b.as_slice().unwrap(), b.0.as_slice().unwrap(),
self.sys.0.as_slice_mut().unwrap(), self.sys.0 .0.as_slice_mut().unwrap(),
self.sys.1.as_slice_mut().unwrap(), self.sys.1 .0.as_slice_mut().unwrap(),
10, 10,
); );
} }
@ -207,7 +208,7 @@ impl<UO: SbpOperator2d + UpwindOperator2d> System<UO> {
RHS_upwind(op, fut, prev, grid, metrics, wb); RHS_upwind(op, fut, prev, grid, metrics, wb);
}; };
let mut _time = 0.0; let mut _time = 0.0;
integrate::integrate::<integrate::Rk4, _, _, _>( integrate::integrate::<integrate::Rk4, Field, _>(
rhs_adaptor, rhs_adaptor,
&self.sys.0, &self.sys.0,
&mut self.sys.1, &mut self.sys.1,

3
multigrid/Cargo.toml
View File

@ -6,9 +6,10 @@ edition = "2018"
[dependencies] [dependencies]
sbp = { path = "../sbp", features = ["rayon", "serde1", "fast-float"] } sbp = { path = "../sbp", features = ["serde1", "fast-float"] }
euler = { path = "../euler", features = ["serde1"] } euler = { path = "../euler", features = ["serde1"] }
hdf5 = "0.7.0" hdf5 = "0.7.0"
integrate = { path = "../utils/integrate", features = ["rayon"] }
rayon = "1.3.0" rayon = "1.3.0"
indicatif = "0.15.0" indicatif = "0.15.0"
structopt = "0.3.14" structopt = "0.3.14"

3
multigrid/src/file.rs
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@ -38,7 +38,8 @@ impl OutputThread {
match self.rx.as_ref().unwrap().try_recv() { match self.rx.as_ref().unwrap().try_recv() {
Ok(mut copy_fields) => { Ok(mut copy_fields) => {
for (from, to) in fields.iter().zip(copy_fields.iter_mut()) { for (from, to) in fields.iter().zip(copy_fields.iter_mut()) {
to.assign(&from); use integrate::Integrable;
euler::Field::assign(to, from);
} }
self.tx self.tx
.as_ref() .as_ref()

2
multigrid/src/main.rs
View File

@ -106,7 +106,7 @@ impl System {
.iter_mut() .iter_mut()
.map(|k| k.as_mut_slice()) .map(|k| k.as_mut_slice())
.collect::<Vec<_>>(); .collect::<Vec<_>>();
sbp::integrate::integrate_multigrid::<sbp::integrate::Rk4, _, _, _>( integrate::integrate_multigrid::<integrate::Rk4, euler::Field, _>(
rhs, rhs,
&self.fnow, &self.fnow,
&mut self.fnext, &mut self.fnext,

1
sbp/Cargo.toml
View File

@ -8,7 +8,6 @@ edition = "2018"
ndarray = { version = "0.14.0", features = ["approx"] } ndarray = { version = "0.14.0", features = ["approx"] }
approx = "0.4.0" approx = "0.4.0"
packed_simd = { version = "0.3.3", package = "packed_simd_2" } packed_simd = { version = "0.3.3", package = "packed_simd_2" }
rayon = { version = "1.3.0", optional = true }
sprs = { version = "0.10.0", optional = true, default-features = false } sprs = { version = "0.10.0", optional = true, default-features = false }
serde = { version = "1.0.115", optional = true, default-features = false, features = ["derive"] } serde = { version = "1.0.115", optional = true, default-features = false, features = ["derive"] }
num-traits = "0.2.14" num-traits = "0.2.14"

2
sbp/src/lib.rs
View File

@ -7,8 +7,6 @@ pub use float::{consts, Float};
/// Grid and grid metrics /// Grid and grid metrics
pub mod grid; pub mod grid;
/// RK operators and methods for implicit integration
pub mod integrate;
/// SBP and interpolation operators /// SBP and interpolation operators
pub mod operators; pub mod operators;
/// General utilities /// General utilities

1
shallow_water/Cargo.toml
View File

@ -8,3 +8,4 @@ edition = "2018"
ndarray = "0.14.0" ndarray = "0.14.0"
sbp = { path = "../sbp" } sbp = { path = "../sbp" }
log = "0.4.8" log = "0.4.8"
integrate = { path = "../utils/integrate" }

18
shallow_water/src/lib.rs
View File

@ -9,15 +9,15 @@ const G: Float = 1.0;
#[derive(Clone, Debug)] #[derive(Clone, Debug)]
pub struct Field(Array3<Float>); pub struct Field(Array3<Float>);
impl<'a> Into<ArrayView3<'a, Float>> for &'a Field { impl integrate::Integrable for Field {
fn into(self) -> ArrayView3<'a, Float> { type State = Field;
self.0.view() type Diff = Field;
}
}
impl<'a> Into<ArrayViewMut3<'a, Float>> for &'a mut Field { fn assign(s: &mut Self::State, o: &Self::State) {
fn into(self) -> ArrayViewMut3<'a, Float> { s.0.assign(&o.0);
self.0.view_mut() }
fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
s.0.scaled_add(scale, &o.0);
} }
} }
@ -301,7 +301,7 @@ impl System {
} }
log::trace!("Iteration complete"); log::trace!("Iteration complete");
}; };
integrate::integrate::<integrate::Rk4, _, _, _>( integrate::integrate::<integrate::Rk4, Field, _>(
rhs, rhs,
&self.fnow, &self.fnow,
&mut self.fnext, &mut self.fnext,

9
utils/integrate/Cargo.toml Normal file
View File

@ -0,0 +1,9 @@
[package]
name = "integrate"
version = "0.1.0"
authors = ["Magnus Ulimoen <magnus@ulimoen.dev>"]
edition = "2018"
[dependencies]
float = { path = "../float/" }
rayon = { version = "1.5.0", optional = true }

129
sbp/src/integrate.rs → utils/integrate/src/lib.rs
View File

@ -8,8 +8,7 @@
//! on the `k` parameter to hold the system state differences. //! on the `k` parameter to hold the system state differences.
//! This parameter is tied to the Butcher Tableau //! This parameter is tied to the Butcher Tableau
use super::Float; use float::Float;
use ndarray::{ArrayView, ArrayViewMut};
/// The Butcher Tableau, with the state transitions described as /// The Butcher Tableau, with the state transitions described as
/// [on wikipedia](https://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods#Explicit_Runge%E2%80%93Kutta_methods). /// [on wikipedia](https://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods#Explicit_Runge%E2%80%93Kutta_methods).
@ -150,6 +149,14 @@ impl EmbeddedButcherTableau for BogackiShampine {
const BSTAR: &'static [Float] = &[7.0 / 24.0, 1.0 / 4.0, 1.0 / 3.0, 1.0 / 8.0]; const BSTAR: &'static [Float] = &[7.0 / 24.0, 1.0 / 4.0, 1.0 / 3.0, 1.0 / 8.0];
} }
pub trait Integrable {
type State;
type Diff;
fn assign(s: &mut Self::State, o: &Self::State);
fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float);
}
#[allow(clippy::too_many_arguments)] #[allow(clippy::too_many_arguments)]
/// Integrates using the [`ButcherTableau`] specified. `rhs` should be the result /// Integrates using the [`ButcherTableau`] specified. `rhs` should be the result
/// of the right hand side of $u_t = rhs$ /// of the right hand side of $u_t = rhs$
@ -159,48 +166,44 @@ impl EmbeddedButcherTableau for BogackiShampine {
/// ///
/// Should be called as /// Should be called as
/// ```rust,ignore /// ```rust,ignore
/// integrate::<Rk4, _, _, _, _>(...) /// integrate::<Rk4, System, _>(...)
/// ``` /// ```
pub fn integrate<BTableau: ButcherTableau, F, RHS, D>( pub fn integrate<BTableau: ButcherTableau, F: Integrable, RHS>(
mut rhs: RHS, mut rhs: RHS,
prev: &F, prev: &F::State,
fut: &mut F, fut: &mut F::State,
time: &mut Float, time: &mut Float,
dt: Float, dt: Float,
k: &mut [F], k: &mut [F::Diff],
) where ) where
for<'r> &'r F: std::convert::Into<ArrayView<'r, Float, D>>, RHS: FnMut(&mut F::Diff, &F::State, Float),
for<'r> &'r mut F: std::convert::Into<ArrayViewMut<'r, Float, D>>,
D: ndarray::Dimension,
RHS: FnMut(&mut F, &F, Float),
{ {
assert_eq!(prev.into().shape(), fut.into().shape());
assert!(k.len() >= BTableau::S); assert!(k.len() >= BTableau::S);
for i in 0.. { for i in 0.. {
let simtime; let simtime;
match i { match i {
0 => { 0 => {
fut.into().assign(&prev.into()); F::assign(fut, prev);
simtime = *time; simtime = *time;
} }
i if i < BTableau::S => { i if i < BTableau::S => {
fut.into().assign(&prev.into()); F::assign(fut, prev);
for (&a, k) in BTableau::A[i - 1].iter().zip(k.iter()) { for (&a, k) in BTableau::A[i - 1].iter().zip(k.iter()) {
if a == 0.0 { if a == 0.0 {
continue; continue;
} }
fut.into().scaled_add(a * dt, &k.into()); F::scaled_add(fut, k, a * dt);
} }
simtime = *time + dt * BTableau::C[i - 1]; simtime = *time + dt * BTableau::C[i - 1];
} }
_ if i == BTableau::S => { _ if i == BTableau::S => {
fut.into().assign(&prev.into()); F::assign(fut, prev);
for (&b, k) in BTableau::B.iter().zip(k.iter()) { for (&b, k) in BTableau::B.iter().zip(k.iter()) {
if b == 0.0 { if b == 0.0 {
continue; continue;
} }
fut.into().scaled_add(b * dt, &k.into()); F::scaled_add(fut, k, b * dt);
} }
*time += dt; *time += dt;
return; return;
@ -219,27 +222,24 @@ pub fn integrate<BTableau: ButcherTableau, F, RHS, D>(
/// ///
/// This produces two results, the most accurate result in `fut`, and the less accurate /// This produces two results, the most accurate result in `fut`, and the less accurate
/// result in `fut2`. This can be used for convergence testing and adaptive timesteps. /// result in `fut2`. This can be used for convergence testing and adaptive timesteps.
pub fn integrate_embedded_rk<BTableau: EmbeddedButcherTableau, F, RHS, D>( pub fn integrate_embedded_rk<BTableau: EmbeddedButcherTableau, F: Integrable, RHS>(
rhs: RHS, rhs: RHS,
prev: &F, prev: &F::State,
fut: &mut F, fut: &mut F::State,
fut2: &mut F, fut2: &mut F::State,
time: &mut Float, time: &mut Float,
dt: Float, dt: Float,
k: &mut [F], k: &mut [F::Diff],
) where ) where
for<'r> &'r F: std::convert::Into<ArrayView<'r, Float, D>>, RHS: FnMut(&mut F::Diff, &F::State, Float),
for<'r> &'r mut F: std::convert::Into<ArrayViewMut<'r, Float, D>>,
RHS: FnMut(&mut F, &F, Float),
D: ndarray::Dimension,
{ {
integrate::<BTableau, F, RHS, D>(rhs, prev, fut, time, dt, k); integrate::<BTableau, F, RHS>(rhs, prev, fut, time, dt, k);
fut2.into().assign(&prev.into()); F::assign(fut2, prev);
for (&b, k) in BTableau::BSTAR.iter().zip(k.iter()) { for (&b, k) in BTableau::BSTAR.iter().zip(k.iter()) {
if b == 0.0 { if b == 0.0 {
continue; continue;
} }
fut2.into().scaled_add(b * dt, &k.into()); F::scaled_add(fut2, k, b * dt);
} }
} }
@ -255,21 +255,19 @@ pub fn integrate_embedded_rk<BTableau: EmbeddedButcherTableau, F, RHS, D>(
/// ///
/// This function requires the `rayon` feature, and is not callable in /// This function requires the `rayon` feature, and is not callable in
/// a `wasm` context. /// a `wasm` context.
pub fn integrate_multigrid<BTableau: ButcherTableau, F, RHS, D>( pub fn integrate_multigrid<BTableau: ButcherTableau, F: Integrable, RHS>(
mut rhs: RHS, mut rhs: RHS,
prev: &[F], prev: &[F::State],
fut: &mut [F], fut: &mut [F::State],
time: &mut Float, time: &mut Float,
dt: Float, dt: Float,
k: &mut [&mut [F]], k: &mut [&mut [F::Diff]],
pool: &rayon::ThreadPool, pool: &rayon::ThreadPool,
) where ) where
for<'r> &'r F: std::convert::Into<ArrayView<'r, Float, D>>, RHS: FnMut(&mut [F::Diff], &[F::State], Float),
for<'r> &'r mut F: std::convert::Into<ArrayViewMut<'r, Float, D>>, F::State: Send + Sync,
RHS: FnMut(&mut [F], &[F], Float), F::Diff: Send + Sync,
F: Send + Sync,
D: ndarray::Dimension,
{ {
for i in 0.. { for i in 0.. {
let simtime; let simtime;
@ -279,8 +277,7 @@ pub fn integrate_multigrid<BTableau: ButcherTableau, F, RHS, D>(
assert!(k.len() >= BTableau::S); assert!(k.len() >= BTableau::S);
for (prev, fut) in prev.iter().zip(fut.iter_mut()) { for (prev, fut) in prev.iter().zip(fut.iter_mut()) {
s.spawn(move |_| { s.spawn(move |_| {
assert_eq!(prev.into().shape(), fut.into().shape()); F::assign(fut, prev);
fut.into().assign(&prev.into());
}); });
} }
}); });
@ -291,12 +288,12 @@ pub fn integrate_multigrid<BTableau: ButcherTableau, F, RHS, D>(
for (ig, (prev, fut)) in prev.iter().zip(fut.iter_mut()).enumerate() { for (ig, (prev, fut)) in prev.iter().zip(fut.iter_mut()).enumerate() {
let k = &k; let k = &k;
s.spawn(move |_| { s.spawn(move |_| {
fut.into().assign(&prev.into()); F::assign(fut, prev);
for (ik, &a) in BTableau::A[i - 1].iter().enumerate() { for (ik, &a) in BTableau::A[i - 1].iter().enumerate() {
if a == 0.0 { if a == 0.0 {
continue; continue;
} }
fut.into().scaled_add(a * dt, &(&k[ik][ig]).into()); F::scaled_add(fut, &k[ik][ig], a * dt);
} }
}); });
} }
@ -308,12 +305,12 @@ pub fn integrate_multigrid<BTableau: ButcherTableau, F, RHS, D>(
for (ig, (prev, fut)) in prev.iter().zip(fut.iter_mut()).enumerate() { for (ig, (prev, fut)) in prev.iter().zip(fut.iter_mut()).enumerate() {
let k = &k; let k = &k;
s.spawn(move |_| { s.spawn(move |_| {
fut.into().assign(&prev.into()); F::assign(fut, prev);
for (ik, &b) in BTableau::B.iter().enumerate() { for (ik, &b) in BTableau::B.iter().enumerate() {
if b == 0.0 { if b == 0.0 {
continue; continue;
} }
fut.into().scaled_add(b * dt, &(&k[ik][ig]).into()); F::scaled_add(fut, &k[ik][ig], b * dt);
} }
}); });
} }
@ -329,3 +326,47 @@ pub fn integrate_multigrid<BTableau: ButcherTableau, F, RHS, D>(
rhs(&mut k[i], &fut, simtime); rhs(&mut k[i], &fut, simtime);
} }
} }
#[test]
/// Solving a second order PDE
fn ballistic() {
#[derive(Clone, Debug)]
struct Ball {
z: Float,
v: Float,
}
impl Integrable for Ball {
type State = Ball;
type Diff = (Float, Float);
fn assign(s: &mut Self::State, o: &Self::State) {
s.z = o.z;
s.v = o.v;
}
fn scaled_add(s: &mut Self::State, o: &Self::Diff, sc: Float) {
s.z += o.0 * sc;
s.v += o.1 * sc;
}
}
let mut t = 0.0;
let dt = 0.001;
let initial = Ball { z: 0.0, v: 10.0 };
let g = -9.81;
let mut k = [(0.0, 0.0); 4];
let gravity = |d: &mut (Float, Float), s: &Ball, _time: Float| {
d.1 = g;
d.0 = s.v
};
let mut next = initial.clone();
//while next.z >= 0.0 {
while t < 1.0 {
let mut next2 = next.clone();
integrate::<EulerMethod, Ball, _>(gravity, &next, &mut next2, &mut t, dt, &mut k);
std::mem::swap(&mut next, &mut next2);
}
let expected_vel = initial.v + g * t;
assert!((next.v - expected_vel).abs() < 1e-3);
let expected_pos = initial.z + initial.v * t + g / 2.0 * t.powi(2);
assert!((next.z - expected_pos).abs() < 1e-2);
}