Prefer clone_from over assign

euler/src/lib.rs

@@ -185,10 +185,19 @@ impl<UO: UpwindOperator2d + SbpOperator2d> System<UO> {
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 /// A 4 x ny x nx array
 pub struct Field(pub(crate) Array3<Float>);
 
+impl Clone for Field {
+    fn clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+    fn clone_from(&mut self, source: &Self) {
+        self.0.clone_from(&source.0)
+    }
+}
+
 #[derive(Clone, Debug)]
 /// A 4 x ny x nx array
 pub struct Diff(pub(crate) Array3<Float>);
@@ -197,9 +206,6 @@ impl integrate::Integrable for Field {
     type State = Field;
     type Diff = Diff;
 
-    fn assign(s: &mut Self::State, o: &Self::State) {
-        s.0.assign(&o.0);
-    }
     fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
         s.0.scaled_add(scale, &o.0);
     }

maxwell/src/lib.rs

@@ -7,16 +7,22 @@ use sbp::Float;
 #[cfg(feature = "sparse")]
 pub mod sparse;
 
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 pub struct Field(pub(crate) Array3<Float>);
 
+impl Clone for Field {
+    fn clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+    fn clone_from(&mut self, source: &Self) {
+        self.0.clone_from(&source.0)
+    }
+}
+
 impl integrate::Integrable for Field {
     type State = Field;
     type Diff = Field;
 
-    fn assign(s: &mut Self::State, o: &Self::State) {
-        s.0.assign(&o.0);
-    }
     fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
         s.0.scaled_add(scale, &o.0);
     }

multigrid/src/file.rs

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

multigrid/src/main.rs

@@ -30,17 +30,7 @@ pub(crate) static MULTITHREAD: AtomicBool = AtomicBool::new(false);
 impl integrate::Integrable for System {
     type State = Vec<euler::Field>;
     type Diff = Vec<euler::Diff>;
-    fn assign(s: &mut Self::State, o: &Self::State) {
-        if MULTITHREAD.load(Ordering::Acquire) {
-            s.par_iter_mut()
-                .zip(o.par_iter())
-                .for_each(|(s, o)| euler::Field::assign(s, o))
-        } else {
-            s.iter_mut()
-                .zip(o.iter())
-                .for_each(|(s, o)| euler::Field::assign(s, o))
-        }
-    }
+
     fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
         if MULTITHREAD.load(Ordering::Acquire) {
             s.par_iter_mut()

shallow_water/src/lib.rs

@@ -6,16 +6,22 @@ use characteristics::{Aminus, Aplus, Bminus, Bplus};
 
 const G: Float = 1.0;
 
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 pub struct Field(Array3<Float>);
 
+impl Clone for Field {
+    fn clone(&self) -> Self {
+        Self(self.0.clone())
+    }
+    fn clone_from(&mut self, source: &Self) {
+        self.0.clone_from(&source.0)
+    }
+}
+
 impl integrate::Integrable for Field {
     type State = Field;
     type Diff = Field;
 
-    fn assign(s: &mut Self::State, o: &Self::State) {
-        s.0.assign(&o.0);
-    }
     fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float) {
         s.0.scaled_add(scale, &o.0);
     }

utils/integrate/src/lib.rs

@@ -152,10 +152,10 @@ impl EmbeddedButcherTableau for BogackiShampine {
 }
 
 pub trait Integrable {
-    type State;
+    /// This type should support `clone_from`
+    type State: Clone;
     type Diff;
 
-    fn assign(s: &mut Self::State, o: &Self::State);
     fn scaled_add(s: &mut Self::State, o: &Self::Diff, scale: Float);
 }
 
@@ -186,11 +186,11 @@ pub fn integrate<BTableau: ButcherTableau, F: Integrable, RHS>(
         let simtime;
         match i {
             0 => {
-                F::assign(fut, prev);
+                fut.clone_from(prev);
                 simtime = *time;
             }
             i if i < BTableau::S => {
-                F::assign(fut, prev);
+                fut.clone_from(prev);
                 for (&a, k) in BTableau::A[i - 1].iter().zip(k.iter()) {
                     if a == 0.0 {
                         continue;
@@ -200,7 +200,7 @@ pub fn integrate<BTableau: ButcherTableau, F: Integrable, RHS>(
                 simtime = *time + dt * BTableau::C[i - 1];
             }
             _ if i == BTableau::S => {
-                F::assign(fut, prev);
+                fut.clone_from(prev);
                 for (&b, k) in BTableau::B.iter().zip(k.iter()) {
                     if b == 0.0 {
                         continue;
@@ -236,7 +236,7 @@ pub fn integrate_embedded_rk<BTableau: EmbeddedButcherTableau, F: Integrable, RH
     RHS: FnMut(&mut F::Diff, &F::State, Float),
 {
     integrate::<BTableau, F, RHS>(rhs, prev, fut, time, dt, k);
-    F::assign(fut2, prev);
+    fut2.clone_from(prev);
     for (&b, k) in BTableau::BSTAR.iter().zip(k.iter()) {
         if b == 0.0 {
             continue;
@@ -256,10 +256,6 @@ fn ballistic() {
     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;