diff -r c5f70e767511 -r f802ddbabcfc src/discrete_gradient.rs
--- a/src/discrete_gradient.rs	Tue Dec 31 08:48:50 2024 -0500
+++ b/src/discrete_gradient.rs	Mon Dec 23 23:27:45 2024 -0500
@@ -7,6 +7,7 @@
 };
 use crate::types::Float;
 use crate::instance::Instance;
+use crate::mapping::ArithmeticTrue;
 use crate::linops::{Mapping, Linear, BoundedLinear, Adjointable, GEMV};
 use crate::norms::{Norm, L2};
 
@@ -258,6 +259,8 @@
     F : Float + nalgebra::RealField,
 {
     type Codomain = DVector<F>;
+    type ArithmeticOptIn = ArithmeticTrue;
+
     fn apply<I : Instance<DVector<F>>>(&self, i : I) -> DVector<F> {
         let mut y = DVector::zeros(N * self.len());
         self.apply_add(&mut y, i);
@@ -302,6 +305,8 @@
     F : Float + nalgebra::RealField,
 {
     type Codomain = DVector<F>;
+    type ArithmeticOptIn = ArithmeticTrue;
+
     fn apply<I : Instance<DVector<F>>>(&self, i : I) -> DVector<F> {
         let mut y = DVector::zeros(self.len());
         self.apply_add(&mut y, i);