Fix StructArray broadcast in VectorOfArray

Fixes #410

This specializes so that if `u.u` is not a vector, it will convert the broadcast to fix that. I couldn't find a nice generic way to use `map` so the fallback is to build the vector and convert, which seems to not be a big performance issue. For StructArrays, `convert(typeof(x), Vector(x))` fails, and so this case is specialized.

Project.toml

@@ -23,6 +23,7 @@ Measurements = "eff96d63-e80a-5855-80a2-b1b0885c5ab7"
 MonteCarloMeasurements = "0987c9cc-fe09-11e8-30f0-b96dd679fdca"
 ReverseDiff = "37e2e3b7-166d-5795-8a7a-e32c996b4267"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
+StructArrays = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
 Tracker = "9f7883ad-71c0-57eb-9f7f-b5c9e6d3789c"
 Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
@@ -33,6 +34,7 @@ RecursiveArrayToolsMeasurementsExt = "Measurements"
 RecursiveArrayToolsMonteCarloMeasurementsExt = "MonteCarloMeasurements"
 RecursiveArrayToolsReverseDiffExt = ["ReverseDiff", "Zygote"]
 RecursiveArrayToolsSparseArraysExt = ["SparseArrays"]
+RecursiveArrayToolsStructArraysExt = "StructArrays"
 RecursiveArrayToolsTrackerExt = "Tracker"
 RecursiveArrayToolsZygoteExt = "Zygote"
 

ext/RecursiveArrayToolsStructArraysExt.jl

@@ -0,0 +1,6 @@
+module RecursiveArrayToolsStructArraysExt
+
+import RecursiveArrayTools, StructArrays
+RecursiveArrayTools.rewrap(::StructArrays.StructArray, u) = StructArrays.StructArray(u)
+
+end

src/vector_of_array.jl

@@ -849,28 +849,33 @@ end
 
 @inline function Base.copy(bc::Broadcast.Broadcasted{<:VectorOfArrayStyle})
     bc = Broadcast.flatten(bc)
-
     parent = find_VoA_parent(bc.args)
 
-    if parent isa AbstractVector
+    u = if parent isa AbstractVector
         # this is the default behavior in v3.15.0
         N = narrays(bc)
-        return VectorOfArray(map(1:N) do i
+        map(1:N) do i
             copy(unpack_voa(bc, i))
-        end)
+        end
     else # if parent isa AbstractArray            
-        return VectorOfArray(map(enumerate(Iterators.product(axes(parent)...))) do (i, _)
+        map(enumerate(Iterators.product(axes(parent)...))) do (i, _)
             copy(unpack_voa(bc, i))
-        end)
+        end
     end
+    VectorOfArray(rewrap(parent, u))
 end
 
+rewrap(::Array,u) = u
+rewrap(parent, u) = convert(typeof(parent), u)
+
 for (type, N_expr) in [
     (Broadcast.Broadcasted{<:VectorOfArrayStyle}, :(narrays(bc))),
     (Broadcast.Broadcasted{<:Broadcast.DefaultArrayStyle}, :(length(dest.u)))
 ]
     @eval @inline function Base.copyto!(dest::AbstractVectorOfArray,
             bc::$type)
+            @show typeof(dest)
+            error()
         bc = Broadcast.flatten(bc)
         N = $N_expr
         @inbounds for i in 1:N

test/copy_static_array_test.jl

@@ -114,3 +114,10 @@ a_voa = VectorOfArray(a)
 a_voa .= 1.0
 @test a_voa[1] == SVector(1.0, 1.0)
 @test a_voa[2] == SVector(1.0, 1.0)
+
+#Broadcast Copy of StructArray
+x = StructArray{SVector{2, Float64}}((randn(2), randn(2)))
+vx = VectorOfArray(x)
+vx2 = copy(vx) .+ 1
+ans = vx .+ vx2
+@test ans.u isa StructArray