Remove non-global Threadpool

utils/integrate/src/lib.rs

@@ -243,90 +243,6 @@ pub fn integrate_embedded_rk<BTableau: EmbeddedButcherTableau, F: Integrable, RH
     }
 }
 
-#[cfg(feature = "rayon")]
-#[allow(clippy::too_many_arguments)]
-/// Integrates a multigrid problem, much the same as [`integrate`],
-/// using a `rayon` threadpool for parallelisation.
-///
-/// note that `rhs` accepts the full system state, and is responsible
-/// for computing the full state difference.
-/// `rhs` can be a mutable closure, so buffers can be used
-/// and mutated inside the closure.
-///
-/// This function requires the `rayon` feature, and is not callable in
-/// a `wasm` context.
-pub fn integrate_multigrid<BTableau: ButcherTableau, F: Integrable, RHS>(
-    mut rhs: RHS,
-    prev: &[F::State],
-    fut: &mut [F::State],
-    time: &mut Float,
-    dt: Float,
-    k: &mut [&mut [F::Diff]],
-
-    pool: &rayon::ThreadPool,
-) where
-    RHS: FnMut(&mut [F::Diff], &[F::State], Float),
-    F::State: Send + Sync,
-    F::Diff: Send + Sync,
-{
-    for i in 0.. {
-        let simtime;
-        match i {
-            0 => {
-                pool.scope(|s| {
-                    assert!(k.len() >= BTableau::S);
-                    for (prev, fut) in prev.iter().zip(fut.iter_mut()) {
-                        s.spawn(move |_| {
-                            F::assign(fut, prev);
-                        });
-                    }
-                });
-                simtime = *time;
-            }
-            i if i < BTableau::S => {
-                pool.scope(|s| {
-                    for (ig, (prev, fut)) in prev.iter().zip(fut.iter_mut()).enumerate() {
-                        let k = &k;
-                        s.spawn(move |_| {
-                            F::assign(fut, prev);
-                            for (ik, &a) in BTableau::A[i - 1].iter().enumerate() {
-                                if a == 0.0 {
-                                    continue;
-                                }
-                                F::scaled_add(fut, &k[ik][ig], a * dt);
-                            }
-                        });
-                    }
-                });
-                simtime = *time + dt * BTableau::C[i - 1];
-            }
-            _ if i == BTableau::S => {
-                pool.scope(|s| {
-                    for (ig, (prev, fut)) in prev.iter().zip(fut.iter_mut()).enumerate() {
-                        let k = &k;
-                        s.spawn(move |_| {
-                            F::assign(fut, prev);
-                            for (ik, &b) in BTableau::B.iter().enumerate() {
-                                if b == 0.0 {
-                                    continue;
-                                }
-                                F::scaled_add(fut, &k[ik][ig], b * dt);
-                            }
-                        });
-                    }
-                });
-                *time += dt;
-                return;
-            }
-            _ => {
-                unreachable!();
-            }
-        };
-
-        rhs(&mut k[i], &fut, simtime);
-    }
-}
-
 #[test]
 /// Solving a second order PDE
 fn ballistic() {