revisit SBP Traits

euler/src/lib.rs

@@ -115,7 +115,7 @@ impl<SBP: SbpOperator2d> System<SBP> {
     }
 }
 
-impl<UO: UpwindOperator2d> System<UO> {
+impl<UO: UpwindOperator2d + SbpOperator2d> System<UO> {
     pub fn advance_upwind(&mut self, dt: Float) {
         let bc = BoundaryCharacteristics {
             north: BoundaryCharacteristic::This,
@@ -558,7 +558,7 @@ pub fn RHS_trad(
 
 #[allow(non_snake_case)]
 pub fn RHS_upwind(
-    op: &dyn UpwindOperator2d,
+    op: &dyn SbpOperator2d,
     k: &mut Field,
     y: &Field,
     metrics: &Metrics,
@@ -583,7 +583,14 @@ pub fn RHS_upwind(
 
     let ad_xi = &mut tmp.4;
     let ad_eta = &mut tmp.5;
-    upwind_dissipation(op, (ad_xi, ad_eta), y, metrics, (&mut tmp.0, &mut tmp.1));
+    let diss_op = op.upwind().expect("This is not an upwind operator");
+    upwind_dissipation(
+        &*diss_op,
+        (ad_xi, ad_eta),
+        y,
+        metrics,
+        (&mut tmp.0, &mut tmp.1),
+    );
 
     azip!((out in &mut k.0,
                     eflux in &dE.0,
@@ -594,7 +601,7 @@ pub fn RHS_upwind(
         *out = (-eflux - fflux + ad_xi + ad_eta)/detj
     });
 
-    SAT_characteristics(op.as_sbp(), k, y, metrics, boundaries);
+    SAT_characteristics(op, k, y, metrics, boundaries);
 }
 
 #[allow(clippy::many_single_char_names)]

maxwell/src/lib.rs

@@ -196,7 +196,7 @@ impl<SBP: SbpOperator2d> System<SBP> {
     }
 }
 
-impl<UO: UpwindOperator2d> System<UO> {
+impl<UO: SbpOperator2d + UpwindOperator2d> System<UO> {
     /// Using artificial dissipation with the upwind operator
     pub fn advance_upwind(&mut self, dt: Float) {
         let op = &self.op;
@@ -271,7 +271,7 @@ fn RHS<SBP: SbpOperator2d>(
 }
 
 #[allow(non_snake_case)]
-fn RHS_upwind<UO: UpwindOperator2d>(
+fn RHS_upwind<UO: SbpOperator2d + UpwindOperator2d>(
     op: &UO,
     k: &mut Field,
     y: &Field,

multigrid/Cargo.toml

@@ -13,7 +13,6 @@ rayon = "1.3.0"
 indicatif = "0.15.0"
 structopt = "0.3.14"
 ndarray = { version = "0.13.1", features = ["serde"] }
-either = "1.5.3"
 serde = { version = "1.0.115", features = ["derive"] }
 json5 = "0.2.8"
 indexmap = { version = "1.5.2", features = ["serde-1"] }

multigrid/src/main.rs

@@ -1,15 +1,12 @@
-use either::*;
 use structopt::StructOpt;
 
-use sbp::operators::{SbpOperator2d, UpwindOperator2d};
+use sbp::operators::SbpOperator2d;
 use sbp::*;
 
 mod file;
 mod parsing;
 use file::*;
 
-pub(crate) type DiffOp = Either<Box<dyn SbpOperator2d>, Box<dyn UpwindOperator2d>>;
-
 struct System {
     fnow: Vec<euler::Field>,
     fnext: Vec<euler::Field>,
@@ -20,14 +17,14 @@ struct System {
     bt: Vec<euler::BoundaryCharacteristics>,
     eb: Vec<euler::BoundaryStorage>,
     time: Float,
-    operators: Vec<DiffOp>,
+    operators: Vec<Box<dyn SbpOperator2d>>,
 }
 
 impl System {
     fn new(
         grids: Vec<grid::Grid>,
         bt: Vec<euler::BoundaryCharacteristics>,
-        operators: Vec<DiffOp>,
+        operators: Vec<Box<dyn SbpOperator2d>>,
     ) -> Self {
         let fnow = grids
             .iter()
@@ -42,10 +39,7 @@ impl System {
         let metrics = grids
             .iter()
             .zip(&operators)
-            .map(|(g, op)| {
+            .map(|(g, op)| g.metrics(&**op).unwrap())
-                let sbpop: &dyn SbpOperator2d = op.as_ref().either(|op| &**op, |uo| uo.as_sbp());
-                g.metrics(sbpop).unwrap()
-            })
             .collect::<Vec<_>>();
 
         let eb = bt
@@ -97,13 +91,10 @@ impl System {
                 {
                     s.spawn(move |_| {
                         let bc = euler::boundary_extracts(prev_all, bt, prev, grid, eb, time);
-                        match op.as_ref() {
+                        if op.upwind().is_some() {
-                            Left(sbp) => {
+                            euler::RHS_upwind(&**op, fut, prev, metrics, &bc, &mut wb.0);
-                                euler::RHS_trad(&**sbp, fut, prev, metrics, &bc, &mut wb.0);
+                        } else {
-                            }
+                            euler::RHS_trad(&**op, fut, prev, metrics, &bc, &mut wb.0);
-                            Right(uo) => {
-                                euler::RHS_upwind(&**uo, fut, prev, metrics, &bc, &mut wb.0);
-                            }
                         }
                     })
                 }
@@ -130,12 +121,10 @@ impl System {
 
     /// Suggested maximum dt for this problem
     fn max_dt(&self) -> Float {
-        let is_h2 = self.operators.iter().any(|op| {
+        let is_h2 = self
-            op.as_ref().either(
+            .operators
-                |op| op.is_h2xi() || op.is_h2eta(),
+            .iter()
-                |op| op.is_h2xi() || op.is_h2eta(),
+            .any(|op| op.is_h2xi() || op.is_h2eta());
-            )
-        });
         let c_max = if is_h2 { 0.5 } else { 1.0 };
         let mut max_dt: Float = Float::INFINITY;
 
@@ -283,8 +272,7 @@ fn main() {
         for ((fmod, grid), op) in sys.fnow.iter().zip(&sys.grids).zip(&sys.operators) {
             let mut fvort = fmod.clone();
             fvort.vortex(grid.x(), grid.y(), time, &vortexparams);
-            let sbpop: &dyn SbpOperator2d = op.as_ref().either(|op| &**op, |uo| uo.as_sbp());
+            e += fmod.h2_err(&fvort, &**op);
-            e += fmod.h2_err(&fvort, sbpop);
         }
         println!("Total error: {:e}", e);
     }

multigrid/src/parsing.rs

@@ -1,5 +1,4 @@
-use super::DiffOp;
+use sbp::operators::SbpOperator2d;
-use either::*;
 use sbp::utils::h2linspace;
 use sbp::Float;
 
@@ -148,7 +147,7 @@ pub struct RuntimeConfiguration {
     pub names: Vec<String>,
     pub grids: Vec<sbp::grid::Grid>,
     pub bc: Vec<euler::BoundaryCharacteristics>,
-    pub op: Vec<DiffOp>,
+    pub op: Vec<Box<dyn SbpOperator2d>>,
     pub integration_time: Float,
     pub vortex: euler::VortexParameters,
 }
@@ -223,32 +222,19 @@ impl Configuration {
 
                 use sbp::operators::*;
                 use Operator as op;
-                match (eta, xi) {
+
-                    (op::Upwind4, op::Upwind4) => {
+                let matcher = |op| -> Box<dyn SbpOperator2d> {
-                        Right(Box::new(Upwind4) as Box<dyn UpwindOperator2d>)
+                    match op {
-                    }
+                        op::Upwind4 => Box::new(Upwind4),
-                    (op::Upwind4h2, op::Upwind4h2) => {
+                        op::Upwind4h2 => Box::new(Upwind4h2),
-                        Right(Box::new(Upwind4h2) as Box<dyn UpwindOperator2d>)
+                        op::Upwind9 => Box::new(Upwind9),
-                    }
+                        op::Upwind9h2 => Box::new(Upwind9h2),
-                    (op::Upwind9, op::Upwind9) => {
+                        op::Sbp4 => Box::new(SBP4),
-                        Right(Box::new(Upwind9) as Box<dyn UpwindOperator2d>)
+                        op::Sbp8 => Box::new(SBP8),
-                    }
-                    (op::Upwind9h2, op::Upwind9h2) => {
-                        Right(Box::new(Upwind9h2) as Box<dyn UpwindOperator2d>)
-                    }
-                    (op::Upwind4, op::Upwind4h2) => {
-                        Right(Box::new((&Upwind4, &Upwind4h2)) as Box<dyn UpwindOperator2d>)
-                    }
-                    (op::Upwind9, op::Upwind9h2) => {
-                        Right(Box::new((&Upwind9, &Upwind9h2)) as Box<dyn UpwindOperator2d>)
-                    }
-                    (op::Upwind9h2, op::Upwind9) => {
-                        Right(Box::new((&Upwind9h2, &Upwind9)) as Box<dyn UpwindOperator2d>)
-                    }
-                    (op::Sbp4, op::Sbp4) => Left(Box::new(SBP4) as Box<dyn SbpOperator2d>),
-                    (op::Sbp8, op::Sbp8) => Left(Box::new(SBP8) as Box<dyn SbpOperator2d>),
-                    _ => todo!("Combination {:?}, {:?} not implemented", eta, xi),
                     }
+                };
+
+                Box::new((matcher(eta), matcher(xi))) as Box<dyn SbpOperator2d>
             })
             .collect();
         let bc = self

sbp/src/operators.rs

@@ -40,80 +40,6 @@ pub trait SbpOperator1d2: SbpOperator1d {
     fn d1_vec(&self, n: usize, front: bool) -> sprs::CsMat<Float>;
 }
 
-pub trait SbpOperator2d: Send + Sync {
-    fn diffxi(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>);
-    fn diffeta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>);
-
-    fn hxi(&self) -> &'static [Float];
-    fn heta(&self) -> &'static [Float];
-
-    fn is_h2xi(&self) -> bool;
-    fn is_h2eta(&self) -> bool;
-
-    fn op_xi(&self) -> &dyn SbpOperator1d;
-    fn op_eta(&self) -> &dyn SbpOperator1d;
-}
-
-impl<SBPeta: SbpOperator1d, SBPxi: SbpOperator1d> SbpOperator2d for (&SBPeta, &SBPxi) {
-    default fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
-        assert_eq!(prev.shape(), fut.shape());
-        for (r0, r1) in prev.outer_iter().zip(fut.outer_iter_mut()) {
-            self.1.diff(r0, r1)
-        }
-    }
-    fn diffeta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
-        let ba = (self.1, self.0);
-        ba.diffxi(prev.reversed_axes(), fut.reversed_axes())
-    }
-    fn hxi(&self) -> &'static [Float] {
-        self.1.h()
-    }
-    fn heta(&self) -> &'static [Float] {
-        self.0.h()
-    }
-    fn is_h2xi(&self) -> bool {
-        self.1.is_h2()
-    }
-    fn is_h2eta(&self) -> bool {
-        self.0.is_h2()
-    }
-
-    fn op_xi(&self) -> &dyn SbpOperator1d {
-        self.1
-    }
-    fn op_eta(&self) -> &dyn SbpOperator1d {
-        self.0
-    }
-}
-
-impl<SBP: SbpOperator1d + Copy> SbpOperator2d for SBP {
-    fn diffxi(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
-        <(&SBP, &SBP) as SbpOperator2d>::diffxi(&(self, self), prev, fut)
-    }
-    fn diffeta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
-        <(&SBP, &SBP) as SbpOperator2d>::diffeta(&(self, self), prev, fut)
-    }
-    fn hxi(&self) -> &'static [Float] {
-        <(&SBP, &SBP) as SbpOperator2d>::hxi(&(self, self))
-    }
-    fn heta(&self) -> &'static [Float] {
-        <(&SBP, &SBP) as SbpOperator2d>::heta(&(self, self))
-    }
-    fn is_h2xi(&self) -> bool {
-        <(&SBP, &SBP) as SbpOperator2d>::is_h2xi(&(self, self))
-    }
-    fn is_h2eta(&self) -> bool {
-        <(&SBP, &SBP) as SbpOperator2d>::is_h2eta(&(self, self))
-    }
-
-    fn op_xi(&self) -> &dyn SbpOperator1d {
-        self
-    }
-    fn op_eta(&self) -> &dyn SbpOperator1d {
-        self
-    }
-}
-
 pub trait UpwindOperator1d: SbpOperator1d + Send + Sync {
     /// Dissipation operator
     fn diss(&self, prev: ArrayView1<Float>, fut: ArrayViewMut1<Float>);
@@ -123,57 +49,55 @@ pub trait UpwindOperator1d: SbpOperator1d + Send + Sync {
     fn diss_matrix(&self, n: usize) -> sprs::CsMat<Float>;
 }
 
-pub trait UpwindOperator2d: SbpOperator2d + Send + Sync {
+pub trait SbpOperator2d: Send + Sync {
-    fn dissxi(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>);
+    fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
-    fn disseta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>);
+        assert_eq!(prev.shape(), fut.shape());
-    fn as_sbp(&self) -> &dyn SbpOperator2d;
+        for (p, f) in prev.outer_iter().zip(fut.outer_iter_mut()) {
+            self.op_xi().diff(p, f)
+        }
+    }
+    fn diffeta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
+        self.diffxi(prev.reversed_axes(), fut.reversed_axes())
+    }
+
+    fn hxi(&self) -> &'static [Float] {
+        self.op_xi().h()
+    }
+    fn heta(&self) -> &'static [Float] {
+        self.op_eta().h()
+    }
+
+    fn is_h2xi(&self) -> bool {
+        self.op_xi().is_h2()
+    }
+    fn is_h2eta(&self) -> bool {
+        self.op_eta().is_h2()
+    }
+
+    fn op_xi(&self) -> &dyn SbpOperator1d;
+    fn op_eta(&self) -> &dyn SbpOperator1d;
+
+    fn upwind(&self) -> Option<Box<dyn UpwindOperator2d>> {
+        None
+    }
+}
+
+pub trait UpwindOperator2d: Send + Sync {
+    fn dissxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
+        assert_eq!(prev.shape(), fut.shape());
+        for (p, f) in prev.outer_iter().zip(fut.outer_iter_mut()) {
+            UpwindOperator2d::op_xi(self).diss(p, f)
+        }
+    }
+    // Assuming operator is symmetrical x/y
+    fn disseta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
+        self.dissxi(prev.reversed_axes(), fut.reversed_axes())
+    }
 
     fn op_xi(&self) -> &dyn UpwindOperator1d;
     fn op_eta(&self) -> &dyn UpwindOperator1d;
 }
 
-impl<UOeta: UpwindOperator1d, UOxi: UpwindOperator1d> UpwindOperator2d for (&UOeta, &UOxi) {
-    default fn dissxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
-        assert_eq!(prev.shape(), fut.shape());
-        for (r0, r1) in prev.outer_iter().zip(fut.outer_iter_mut()) {
-            self.1.diss(r0, r1);
-        }
-    }
-    fn disseta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
-        let ba = (self.1, self.0);
-        ba.dissxi(prev.reversed_axes(), fut.reversed_axes())
-    }
-    fn as_sbp(&self) -> &dyn SbpOperator2d {
-        self
-    }
-
-    fn op_xi(&self) -> &dyn UpwindOperator1d {
-        self.1
-    }
-    fn op_eta(&self) -> &dyn UpwindOperator1d {
-        self.0
-    }
-}
-
-impl<UO: UpwindOperator1d + Copy> UpwindOperator2d for UO {
-    fn dissxi(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
-        <(&UO, &UO) as UpwindOperator2d>::dissxi(&(self, self), prev, fut)
-    }
-    fn disseta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
-        <(&UO, &UO) as UpwindOperator2d>::disseta(&(self, self), prev, fut)
-    }
-    fn as_sbp(&self) -> &dyn SbpOperator2d {
-        self
-    }
-
-    fn op_xi(&self) -> &dyn UpwindOperator1d {
-        self
-    }
-    fn op_eta(&self) -> &dyn UpwindOperator1d {
-        self
-    }
-}
-
 pub trait InterpolationOperator: Send + Sync {
     /// Interpolation from a grid with twice resolution
     fn fine2coarse(&self, fine: ArrayView1<Float>, coarse: ArrayViewMut1<Float>);
@@ -181,6 +105,37 @@ pub trait InterpolationOperator: Send + Sync {
     fn coarse2fine(&self, coarse: ArrayView1<Float>, fine: ArrayViewMut1<Float>);
 }
 
+impl SbpOperator2d for (Box<dyn SbpOperator2d>, Box<dyn SbpOperator2d>) {
+    fn diffxi(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
+        self.1.diffxi(prev, fut)
+    }
+    fn diffeta(&self, prev: ArrayView2<Float>, fut: ArrayViewMut2<Float>) {
+        self.0.diffeta(prev, fut)
+    }
+
+    fn op_xi(&self) -> &dyn SbpOperator1d {
+        self.1.op_xi()
+    }
+    fn op_eta(&self) -> &dyn SbpOperator1d {
+        self.0.op_eta()
+    }
+    fn upwind(&self) -> Option<Box<dyn UpwindOperator2d>> {
+        match (self.0.upwind(), self.1.upwind()) {
+            (Some(u), Some(v)) => Some(Box::new((u, v))),
+            _ => None,
+        }
+    }
+}
+
+impl UpwindOperator2d for (Box<dyn UpwindOperator2d>, Box<dyn UpwindOperator2d>) {
+    fn op_xi(&self) -> &dyn UpwindOperator1d {
+        self.1.op_xi()
+    }
+    fn op_eta(&self) -> &dyn UpwindOperator1d {
+        self.0.op_eta()
+    }
+}
+
 #[inline(always)]
 fn diff_op_1d(
     block: &[&[Float]],

sbp/src/operators/traditional4.rs

@@ -71,7 +71,7 @@ impl SbpOperator1d for SBP4 {
     }
 }
 
-impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &SBP4) {
+impl SbpOperator2d for SBP4 {
     fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * SBP4::BLOCK.len());
@@ -95,6 +95,12 @@ impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &SBP4) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
 }
 
 impl super::SbpOperator1d2 for SBP4 {

sbp/src/operators/traditional8.rs

@@ -59,7 +59,7 @@ impl SbpOperator1d for SBP8 {
     }
 }
 
-impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &SBP8) {
+impl SbpOperator2d for SBP8 {
     fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * SBP8::BLOCK.len());
@@ -83,6 +83,12 @@ impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &SBP8) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
 }
 
 #[test]

sbp/src/operators/upwind4.rs

@@ -229,7 +229,7 @@ impl SbpOperator1d for Upwind4 {
     }
 }
 
-impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind4) {
+impl SbpOperator2d for Upwind4 {
     fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind4::BLOCK.len());
@@ -259,6 +259,15 @@ impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind4) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn upwind(&self) -> Option<Box<dyn UpwindOperator2d>> {
+        Some(Box::new(Self))
+    }
 }
 
 #[test]
@@ -377,7 +386,7 @@ impl UpwindOperator1d for Upwind4 {
     }
 }
 
-impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind4) {
+impl UpwindOperator2d for Upwind4 {
     fn dissxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind4::BLOCK.len());
@@ -407,6 +416,13 @@ impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind4) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+
+    fn op_xi(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
 }
 
 #[test]

sbp/src/operators/upwind4h2.rs

@@ -77,7 +77,7 @@ impl SbpOperator1d for Upwind4h2 {
     }
 }
 
-impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind4h2) {
+impl SbpOperator2d for Upwind4h2 {
     fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind4h2::BLOCK.len());
@@ -101,9 +101,18 @@ impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind4h2) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn upwind(&self) -> Option<Box<dyn UpwindOperator2d>> {
+        Some(Box::new(Self))
+    }
 }
 
-impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind4h2) {
+impl UpwindOperator2d for Upwind4h2 {
     fn dissxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind4h2::BLOCK.len());
@@ -137,6 +146,12 @@ impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind4h2) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
 }
 
 #[test]

sbp/src/operators/upwind9.rs

@@ -82,7 +82,7 @@ impl SbpOperator1d for Upwind9 {
     }
 }
 
-impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind9) {
+impl SbpOperator2d for Upwind9 {
     fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind9::BLOCK.len());
@@ -106,6 +106,15 @@ impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind9) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn upwind(&self) -> Option<Box<dyn UpwindOperator2d>> {
+        Some(Box::new(Self))
+    }
 }
 
 impl UpwindOperator1d for Upwind9 {
@@ -136,7 +145,7 @@ impl UpwindOperator1d for Upwind9 {
     }
 }
 
-impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind9) {
+impl UpwindOperator2d for Upwind9 {
     fn dissxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind9::BLOCK.len());
@@ -160,6 +169,12 @@ impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind9) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
 }
 
 #[test]

sbp/src/operators/upwind9h2.rs

@@ -85,7 +85,7 @@ impl SbpOperator1d for Upwind9h2 {
     }
 }
 
-impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind9h2) {
+impl SbpOperator2d for Upwind9h2 {
     fn diffxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind9h2::BLOCK.len());
@@ -109,6 +109,15 @@ impl<SBP: SbpOperator1d> SbpOperator2d for (&SBP, &Upwind9h2) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn SbpOperator1d {
+        &Self
+    }
+    fn upwind(&self) -> Option<Box<dyn UpwindOperator2d>> {
+        Some(Box::new(Self))
+    }
 }
 
 #[test]
@@ -163,7 +172,7 @@ impl UpwindOperator1d for Upwind9h2 {
     }
 }
 
-impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind9h2) {
+impl UpwindOperator2d for Upwind9h2 {
     fn dissxi(&self, prev: ArrayView2<Float>, mut fut: ArrayViewMut2<Float>) {
         assert_eq!(prev.shape(), fut.shape());
         assert!(prev.shape()[1] >= 2 * Upwind9h2::BLOCK.len());
@@ -197,4 +206,10 @@ impl<UO: UpwindOperator1d> UpwindOperator2d for (&UO, &Upwind9h2) {
             _ => unreachable!("Should only be two elements in the strides vectors"),
         }
     }
+    fn op_xi(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
+    fn op_eta(&self) -> &dyn UpwindOperator1d {
+        &Self
+    }
 }

shallow_water/src/lib.rs

@@ -62,7 +62,7 @@ pub struct System {
     fnext: Field,
     x: (Float, Float, usize),
     y: (Float, Float, usize),
-    op: Box<dyn operators::UpwindOperator2d>,
+    op: Box<dyn operators::SbpOperator2d>,
     k: [Field; 4],
 }
 
@@ -175,6 +175,7 @@ impl System {
 
             // Upwind dissipation
             if false {
+                if let Some(op) = op.upwind() {
                     let mut temp_dx = temp_dy;
                     azip!((dest in &mut temp, eta in now.eta(), etau in now.etau()) {
                         *dest = -(eta.powf(3.0/2.0)*G.sqrt() + etau.abs())/eta
@@ -205,6 +206,7 @@ impl System {
                         *dest -= etav*diss;
                     });
                 }
+            }
 
             // SAT boundaries
             #[derive(Debug)]