Move StaticArrays support to extension (#265)

* Use weakdeps on Julia v1.9

Update Project.toml

* move StructStaticArray broadcast to ext

* fix doctest

* move `Adapt` to ext

And use curried adapter to avoid possible instability

* Apply suggestions from code review

* Adopt code style suggestion.

* restrict Adapt compat

* Add empty bc test.

* define `__broadcast` ourselves

---------

Co-authored-by: Oliver Schulz <oschulz@mpp.mpg.de>

Author: N5N3

Project.toml

@@ -7,21 +7,32 @@ Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
 ConstructionBase = "187b0558-2788-49d3-abe0-74a17ed4e7c9"
 DataAPI = "9a962f9c-6df0-11e9-0e5d-c546b8b5ee8a"
 GPUArraysCore = "46192b85-c4d5-4398-a991-12ede77f4527"
-StaticArraysCore = "1e83bf80-4336-4d27-bf5d-d5a4f845583c"
+StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 
+[weakdeps]
+Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
+GPUArraysCore = "46192b85-c4d5-4398-a991-12ede77f4527"
+StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
+
+[extensions]
+StructArraysAdaptExt = "Adapt"
+StructArraysGPUArraysCoreExt = "GPUArraysCore"
+StructArraysStaticArraysExt = "StaticArrays"
+
 [compat]
-Adapt = "1, 2, 3"
+Adapt = "3.4"
 ConstructionBase = "1"
 DataAPI = "1"
 GPUArraysCore = "0.1.2"
 StaticArrays = "1.5.6"
-StaticArraysCore = "1.3"
 Tables = "1"
 julia = "1.6"
 
 [extras]
+Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
+GPUArraysCore = "46192b85-c4d5-4398-a991-12ede77f4527"
 JLArrays = "27aeb0d3-9eb9-45fb-866b-73c2ecf80fcb"
 OffsetArrays = "6fe1bfb0-de20-5000-8ca7-80f57d26f881"
 PooledArrays = "2dfb63ee-cc39-5dd5-95bd-886bf059d720"
@@ -32,4 +43,4 @@ TypedTables = "9d95f2ec-7b3d-5a63-8d20-e2491e220bb9"
 WeakRefStrings = "ea10d353-3f73-51f8-a26c-33c1cb351aa5"
 
 [targets]
-test = ["Test", "JLArrays", "StaticArrays", "OffsetArrays", "PooledArrays", "TypedTables", "WeakRefStrings", "Documenter", "SparseArrays"]
+test = ["Test", "JLArrays", "StaticArrays", "OffsetArrays", "PooledArrays", "TypedTables", "WeakRefStrings", "Documenter", "SparseArrays", "GPUArraysCore", "Adapt"]

docs/src/advanced.md

@@ -6,89 +6,56 @@ StructArrays support structures with custom data layout. The user is required to
 
 Here is an example of a type `MyType` that has as custom fields either its field `data` or fields of its field `rest` (which is a named tuple):
 
-```jldoctest advanced1
-julia> using StructArrays
+```@repl advanced1
+using StructArrays
 
-julia> struct MyType{T, NT<:NamedTuple}
-           data::T
-           rest::NT
-       end
+struct MyType{T, NT<:NamedTuple}
+    data::T
+    rest::NT
+end
 
-julia> MyType(x; kwargs...) = MyType(x, values(kwargs))
-MyType
+MyType(x; kwargs...) = MyType(x, values(kwargs))
 ```
 
 Let's create a small array of these objects:
 
-```jldoctest advanced1
-julia> s = [MyType(i/5, a=6-i, b=2) for i in 1:5]
-5-element Vector{MyType{Float64, NamedTuple{(:a, :b), Tuple{Int64, Int64}}}}:
- MyType{Float64, NamedTuple{(:a, :b), Tuple{Int64, Int64}}}(0.2, (a = 5, b = 2))
- MyType{Float64, NamedTuple{(:a, :b), Tuple{Int64, Int64}}}(0.4, (a = 4, b = 2))
- MyType{Float64, NamedTuple{(:a, :b), Tuple{Int64, Int64}}}(0.6, (a = 3, b = 2))
- MyType{Float64, NamedTuple{(:a, :b), Tuple{Int64, Int64}}}(0.8, (a = 2, b = 2))
- MyType{Float64, NamedTuple{(:a, :b), Tuple{Int64, Int64}}}(1.0, (a = 1, b = 2))
+```@repl advanced1
+s = [MyType(i/5, a=6-i, b=2) for i in 1:5]
 ```
 
 The default `StructArray` does not unpack the `NamedTuple`:
 
-```jldoctest advanced1
-julia> sa = StructArray(s);
-
-julia> sa.rest
-5-element Vector{NamedTuple{(:a, :b), Tuple{Int64, Int64}}}:
- (a = 5, b = 2)
- (a = 4, b = 2)
- (a = 3, b = 2)
- (a = 2, b = 2)
- (a = 1, b = 2)
-
-julia> sa.a
-ERROR: type NamedTuple has no field a
-Stacktrace:
- [1] component
-[...]
+```@repl advanced1
+sa = StructArray(s);
+sa.rest
+sa.a
 ```
 
 Suppose we wish to give the keywords their own fields. We can define custom `staticschema`, `component`, and `createinstance` methods for `MyType`:
 
-```jldoctest advanced1
-julia> function StructArrays.staticschema(::Type{MyType{T, NamedTuple{names, types}}}) where {T, names, types}
-           # Define the desired names and eltypes of the "fields"
-           return NamedTuple{(:data, names...), Base.tuple_type_cons(T, types)}
-       end;
-
-julia> function StructArrays.component(m::MyType, key::Symbol)
-            # Define a component-extractor
-            return key === :data ? getfield(m, 1) : getfield(getfield(m, 2), key)
-       end;
-
-julia> function StructArrays.createinstance(::Type{MyType{T, NT}}, x, args...) where {T, NT}
-            # Generate an instance of MyType from components
-            return MyType(x, NT(args))
-       end;
+```@repl advanced1
+function StructArrays.staticschema(::Type{MyType{T, NamedTuple{names, types}}}) where {T, names, types}
+    # Define the desired names and eltypes of the "fields"
+    return NamedTuple{(:data, names...), Base.tuple_type_cons(T, types)}
+end;
+
+function StructArrays.component(m::MyType, key::Symbol)
+    # Define a component-extractor
+    return key === :data ? getfield(m, 1) : getfield(getfield(m, 2), key)
+end;
+
+function StructArrays.createinstance(::Type{MyType{T, NT}}, x, args...) where {T, NT}
+    # Generate an instance of MyType from components
+    return MyType(x, NT(args))
+end;
 ```
 
 and now:
 
-```jldoctest advanced1
-julia> sa = StructArray(s);
-
-julia> sa.a
-5-element Vector{Int64}:
- 5
- 4
- 3
- 2
- 1
-
-julia> sa.b
-5-element Vector{Int64}:
- 2
- 2
- 2
- 2
- 2
+```@repl advanced1
+sa = StructArray(s);
+sa.a
+sa.b
 ```
 
 The above strategy has been tested and implemented in [GeometryBasics.jl](https://github.com/JuliaGeometry/GeometryBasics.jl).

docs/src/index.md

@@ -9,73 +9,39 @@ The package was largely inspired by the `Columns` type in [IndexedTables](https:
 ## Collection and initialization
 
 One can create a `StructArray` by providing the struct type and a tuple or NamedTuple of field arrays:
-```jldoctest intro
-julia> using StructArrays
-
-julia> struct Foo{T}
-           a::T
-           b::T
-       end
-
-julia> adata = [1 2; 3 4]; bdata = [10 20; 30 40];
-
-julia> x = StructArray{Foo}((adata, bdata))
-2×2 StructArray(::Matrix{Int64}, ::Matrix{Int64}) with eltype Foo:
- Foo{Int64}(1, 10)  Foo{Int64}(2, 20)
- Foo{Int64}(3, 30)  Foo{Int64}(4, 40)
+```@repl intro
+using StructArrays
+struct Foo{T}
+    a::T
+    b::T
+end
+adata = [1 2; 3 4]; bdata = [10 20; 30 40];
+x = StructArray{Foo}((adata, bdata))
 ```
 
 You can also initialze a StructArray by passing in a NamedTuple, in which case the name (rather than the order) specifies how the input arrays are assigned to fields:
 
-```jldoctest intro
-julia> x = StructArray{Foo}((b = adata, a = bdata))    # initialize a with bdata and vice versa
-2×2 StructArray(::Matrix{Int64}, ::Matrix{Int64}) with eltype Foo:
- Foo{Int64}(10, 1)  Foo{Int64}(20, 2)
- Foo{Int64}(30, 3)  Foo{Int64}(40, 4)
+```@repl intro
+x = StructArray{Foo}((b = adata, a = bdata))    # initialize a with bdata and vice versa
 ```
 
 If a struct is not specified, a StructArray with Tuple or NamedTuple elements will be created:
-```jldoctest intro
-julia> x = StructArray((adata, bdata))
-2×2 StructArray(::Matrix{Int64}, ::Matrix{Int64}) with eltype Tuple{Int64, Int64}:
- (1, 10)  (2, 20)
- (3, 30)  (4, 40)
-
-julia> x = StructArray((a = adata, b = bdata))
-2×2 StructArray(::Matrix{Int64}, ::Matrix{Int64}) with eltype NamedTuple{(:a, :b), Tuple{Int64, Int64}}:
- (a = 1, b = 10)  (a = 2, b = 20)
- (a = 3, b = 30)  (a = 4, b = 40)
+```@repl intro
+x = StructArray((adata, bdata))
+x = StructArray((a = adata, b = bdata))
 ```
 
 It's also possible to create a `StructArray` by choosing a particular dimension to interpret as the components of a struct:
 
-```jldoctest intro
-julia> x = StructArray{Complex{Int}}(adata; dims=1)  # along dimension 1, the first item `re` and the second is `im`
-2-element StructArray(view(::Matrix{Int64}, 1, :), view(::Matrix{Int64}, 2, :)) with eltype Complex{Int64}:
- 1 + 3im
- 2 + 4im
-
-julia> x = StructArray{Complex{Int}}(adata; dims=2)  # along dimension 2, the first item `re` and the second is `im`
-2-element StructArray(view(::Matrix{Int64}, :, 1), view(::Matrix{Int64}, :, 2)) with eltype Complex{Int64}:
- 1 + 2im
- 3 + 4im
+```@repl intro
+x = StructArray{Complex{Int}}(adata; dims=1)  # along dimension 1, the first item `re` and the second is `im`
+x = StructArray{Complex{Int}}(adata; dims=2)  # along dimension 2, the first item `re` and the second is `im`
 ```
 
 One can also create a `StructArray` from an iterable of structs without creating an intermediate `Array`:
 
-```jldoctest intro
-julia> StructArray(log(j+2.0*im) for j in 1:10)
-10-element StructArray(::Vector{Float64}, ::Vector{Float64}) with eltype ComplexF64:
- 0.8047189562170501 + 1.1071487177940904im
- 1.0397207708399179 + 0.7853981633974483im
- 1.2824746787307684 + 0.5880026035475675im
- 1.4978661367769954 + 0.4636476090008061im
-  1.683647914993237 + 0.3805063771123649im
- 1.8444397270569681 + 0.3217505543966422im
-  1.985145956776061 + 0.27829965900511133im
- 2.1097538525880535 + 0.24497866312686414im
- 2.2213256282451583 + 0.21866894587394195im
- 2.3221954495706862 + 0.19739555984988078im
+```@repl intro
+StructArray(log(j+2.0*im) for j in 1:10)
 ```
 
 Another option is to create an uninitialized `StructArray` and then fill it with data. Just like in normal arrays, this is done with the `undef` syntax:

ext/StructArraysAdaptExt.jl

@@ -0,0 +1,5 @@
+module StructArraysAdaptExt
+# Use Adapt allows for automatic conversion of CPU to GPU StructArrays
+using Adapt, StructArrays
+Adapt.adapt_structure(to, s::StructArray) = replace_storage(adapt(to), s)
+end

ext/StructArraysGPUArraysCoreExt.jl

@@ -0,0 +1,21 @@
+module StructArraysGPUArraysCoreExt
+
+using StructArrays
+using StructArrays: map_params, array_types
+
+using Base: tail
+
+import GPUArraysCore
+
+# for GPU broadcast
+import GPUArraysCore
+function GPUArraysCore.backend(::Type{T}) where {T<:StructArray}
+    backends = map_params(GPUArraysCore.backend, array_types(T))
+    backend, others = backends[1], tail(backends)
+    isconsistent = mapfoldl(isequal(backend), &, others; init=true)
+    isconsistent || throw(ArgumentError("all component arrays must have the same GPU backend"))
+    return backend
+end
+StructArrays.always_struct_broadcast(::GPUArraysCore.AbstractGPUArrayStyle) = true
+
+end # module

ext/StructArraysStaticArraysExt.jl

@@ -0,0 +1,107 @@
+module StructArraysStaticArraysExt
+
+using StructArrays
+using StaticArrays: StaticArray, FieldArray, tuple_prod
+
+"""
+    StructArrays.staticschema(::Type{<:StaticArray{S, T}}) where {S, T}
+
+The `staticschema` of a `StaticArray` element type is the `staticschema` of the underlying `Tuple`.
+```julia
+julia> StructArrays.staticschema(SVector{2, Float64})
+Tuple{Float64, Float64}
+```
+The one exception to this rule is `<:StaticArrays.FieldArray`, since `FieldArray` is based on a 
+struct. In this case, `staticschema(<:FieldArray)` returns the `staticschema` for the struct 
+which subtypes `FieldArray`. 
+"""
+@generated function StructArrays.staticschema(::Type{<:StaticArray{S, T}}) where {S, T}
+    return quote
+        Base.@_inline_meta
+        return NTuple{$(tuple_prod(S)), T}
+    end
+end
+StructArrays.createinstance(::Type{T}, args...) where {T<:StaticArray} = T(args)
+StructArrays.component(s::StaticArray, i) = getindex(s, i)
+
+# invoke general fallbacks for a `FieldArray` type.
+@inline function StructArrays.staticschema(T::Type{<:FieldArray})
+    invoke(StructArrays.staticschema, Tuple{Type{<:Any}}, T)
+end
+StructArrays.component(s::FieldArray, i) = invoke(StructArrays.component, Tuple{Any, Any}, s, i)
+StructArrays.createinstance(T::Type{<:FieldArray}, args...) = invoke(StructArrays.createinstance, Tuple{Type{<:Any}, Vararg}, T, args...)
+
+# Broadcast overload
+using StaticArrays: StaticArrayStyle, similar_type, Size, SOneTo
+using StaticArrays: broadcast_flatten, broadcast_sizes, first_statictype
+using StructArrays: isnonemptystructtype
+using Base.Broadcast: Broadcasted, _broadcast_getindex
+
+# StaticArrayStyle has no similar defined.
+# Overload `try_struct_copy` instead.
+@inline function StructArrays.try_struct_copy(bc::Broadcasted{StaticArrayStyle{M}}) where {M}
+    flat = broadcast_flatten(bc); as = flat.args; f = flat.f
+    argsizes = broadcast_sizes(as...)
+    ax = axes(bc)
+    ax isa Tuple{Vararg{SOneTo}} || error("Dimension is not static. Please file a bug at `StaticArrays.jl`.")
+    return _broadcast(f, Size(map(length, ax)), argsizes, as...)
+end
+
+# A functor generates the ith component of StructStaticBroadcast.
+struct Similar_ith{SA, E<:Tuple}
+    elements::E
+    Similar_ith{SA}(elements::Tuple) where {SA} = new{SA, typeof(elements)}(elements)
+end
+function (s::Similar_ith{SA})(i::Int) where {SA}
+    ith_elements = ntuple(Val(length(s.elements))) do j
+        getfield(s.elements[j], i)
+    end
+    ith_SA = similar_type(SA, fieldtype(eltype(SA), i))
+    return @inbounds ith_SA(ith_elements)
+end
+
+@inline function _broadcast(f, sz::Size{newsize}, s::Tuple{Vararg{Size}}, a...) where {newsize}
+    first_staticarray = first_statictype(a...)
+    elements, ET = if prod(newsize) == 0
+        # Use inference to get eltype in empty case (following StaticBroadcast defined in StaticArrays.jl)
+        eltys = Tuple{map(eltype, a)...}
+        (), Core.Compiler.return_type(f, eltys)
+    else
+        temp = __broadcast(f, sz, s, a...)
+        temp, eltype(temp)
+    end
+    if isnonemptystructtype(ET)
+        SA = similar_type(first_staticarray, ET, sz)
+        arrs = ntuple(Similar_ith{SA}(elements), Val(fieldcount(ET)))
+        return StructArray{ET}(arrs)
+    else
+        @inbounds return similar_type(first_staticarray, ET, sz)(elements)
+    end
+end
+
+# The `__broadcast` kernal is copied from `StaticArrays.jl`.
+# see https://github.com/JuliaArrays/StaticArrays.jl/blob/master/src/broadcast.jl
+@generated function __broadcast(f, ::Size{newsize}, s::Tuple{Vararg{Size}}, a...) where newsize
+    sizes = [sz.parameters[1] for sz ∈ s.parameters]
+
+    indices = CartesianIndices(newsize)
+    exprs = similar(indices, Expr)
+    for (j, current_ind) ∈ enumerate(indices)
+        exprs_vals = (broadcast_getindex(sz, i, current_ind) for (i, sz) in enumerate(sizes))
+        exprs[j] = :(f($(exprs_vals...)))
+    end
+
+    return quote
+        Base.@_inline_meta
+        return tuple($(exprs...))
+    end
+end
+
+broadcast_getindex(::Tuple{}, i::Int, I::CartesianIndex) = return :(_broadcast_getindex(a[$i], $I))
+function broadcast_getindex(oldsize::Tuple, i::Int, newindex::CartesianIndex)
+    li = LinearIndices(oldsize)
+    ind = _broadcast_getindex(li, newindex)
+    return :(a[$i][$ind])
+end
+
+end