fix: minor fixes

docs/src/manual/differentiability.md

@@ -9,7 +9,7 @@ IncompressibleNavierStokes is
 which means that you can back-propagate gradients through the code.
 This comes at a cost however, as intermediate velocity fields need to be stored
 in memory for use in the backward pass. For this reason, many of the operators
-come in two versions:oa slow differentiable allocating non-mutating variant (e.g.
+come in two versions: a slow differentiable allocating non-mutating variant (e.g.
 [`divergence`](@ref)) and fast non-differentiable non-allocating mutating
 variant (e.g. [`divergence!`](@ref).)
 
@@ -26,7 +26,8 @@ make a time stepping loop composed of differentiable operations:
 
 ```julia
 import IncompressibleNavierStokes as INS
-setup = INS.Setup(; x = (0:0.01:1, 0:0.01:1), Re = 500.0)
+ax = range(0, 1, 101)
+setup = INS.Setup(; x = (ax, ax), Re = 500.0)
 psolver = INS.default_psolver(setup)
 method = INS.RKMethods.RK44P2()
 Δt = 0.01
@@ -38,16 +39,15 @@ function final_energy(u)
         stepper = INS.timestep(method, stepper, Δt)
     end
     (; u) = stepper
-    sum(abs2, u[1][Iu[1]]) / 2 + sum(abs2, u[2][Iu[2]]) / 2
+    sum(abs2, u[Iu[1], 1]) / 2 + sum(abs2, u[Iu[2], 2]) / 2
 end
 
 u = INS.random_field(setup)
 
 using Zygote
 g, = Zygote.gradient(final_energy, u)
 
-@show size.(u)
-@show size.(g)
+@show size(u) size(g)
 ```
 
 Now `g` is the gradient of `final_energy` with respect to the initial conditions

examples/Kolmogorov2D.jl

@@ -39,7 +39,7 @@ ustart = random_field(setup, 0.0; A = 1e-2);
 #
 # Since the force is steady, it is just stored as a field.
 
-heatmap(setup.bodyforce[1])
+heatmap(setup.bodyforce[:, :, 1])
 
 # ## Solve unsteady problem
 

src/initializers.jl

@@ -202,7 +202,7 @@ function random_field(
         all(==((PeriodicBC(), PeriodicBC())), boundary_conditions),
         "Random field requires periodic boundary conditions."
     )
-    @assert all(Δ -> all(≈(0), diff(Δ)), Δ) "Random field requires uniform grid spacing."
+    @assert all(Δ -> all(≈(Δ[1]), Δ), Δ) "Random field requires uniform grid spacing."
     @assert all(iseven, N) "Random field requires even number of volumes."
 
     # Create random velocity field

src/operators.jl

@@ -1157,8 +1157,7 @@ function interpolate_u_p!(up, u, setup)
         up[I, α] = (u[I-e(α), α] + u[I, α]) / 2
     end
     for α = 1:D
-        I0 = first(Ip)
-        I0 -= oneunit(I0)
+        I0 = getoffset(Ip)
         int!(backend, workgroupsize)(up, u, Val(α), I0; ndrange = Np)
     end
     up

src/processors.jl

@@ -149,9 +149,11 @@ function observefield(
             interpolate_u_p!(up, u, setup)
             # map((u, v, w) -> √sum(u^2 + v^2 + w^2), up...)
             if D == 2
-                @. upnorm = sqrt(up[1]^2 + up[2]^2)
+                uptuple = eachslice(up; dims = ndims(up))
+                @. upnorm = sqrt(uptuple[1]^2 + uptuple[2]^2)
             elseif D == 3
-                @. upnorm = sqrt(up[1]^2 + up[2]^2 + up[3]^2)
+                uptuple = eachslice(up; dims = ndims(up))
+                @. upnorm = sqrt(uptuple[1]^2 + uptuple[2]^2 + uptuple[3]^2)
             end
         elseif fieldname == :vorticity
             apply_bc_u!(u, t, setup)