--- a/src/SbpOperators/volumeops/derivatives/first_derivative.jl	Tue Nov 01 22:44:00 2022 +0100
+++ b/src/SbpOperators/volumeops/derivatives/first_derivative.jl	Fri Feb 10 08:36:56 2023 +0100
@@ -7,14 +7,16 @@
 `direction`, using the stencil `inner_stencil` in the interior and a set of stencils `closure_stencils`
 for the points in the closure regions.
 
-On a one-dimensional `grid`, `D1` is a `VolumeOperator`. On a multi-dimensional `grid`, `D1` is the outer product of the
-one-dimensional operator with the `IdentityTensor`s in orthogonal coordinate dirrections.
+On a one-dimensional `grid`, `D1` is a `VolumeOperator`. On a multi-dimensional `grid`, `D1` is the inflation of
+a `VolumeOperator`.
 
-See also: [`volume_operator`](@ref).
+See also: [`VolumeOperator`](@ref), [`LazyTensors.inflate`](@ref).
 """
 function first_derivative(grid::EquidistantGrid, inner_stencil, closure_stencils, direction)
     h_inv = inverse_spacing(grid)[direction]
-    return SbpOperators.volume_operator(grid, scale(inner_stencil,h_inv), scale.(closure_stencils,h_inv), odd, direction)
+
+    D₁ = VolumeOperator(restrict(grid, direction), scale(inner_stencil,h_inv), scale.(closure_stencils,h_inv), odd)
+    return LazyTensors.inflate(D₁, size(grid), direction)
 end