Add tests and docs for to/from_parent_dims

Author: Tokazama

Project.toml

@@ -1,6 +1,6 @@
 name = "ArrayInterface"
 uuid = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
-version = "3"
+version = "3.0.0"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/dimensions.jl

@@ -18,6 +18,11 @@ function is_increasing(perm::Tuple{StaticInt{X},StaticInt{Y}}) where {X, Y}
 end
 is_increasing(::Tuple{StaticInt{X}}) where {X} = True()
 
+"""
+    from_parent_dims(::Type{T}) -> Bool
+
+Returns the mapping from parent dimensions to child dimensions.
+"""
 from_parent_dims(::Type{T}) where {T} = nstatic(Val(ndims(T)))
 from_parent_dims(::Type{T}) where {T<:Union{Transpose,Adjoint}} = (StaticInt(2), One())
 from_parent_dims(::Type{<:SubArray{T,N,A,I}}) where {T,N,A,I} = _from_sub_dims(A, I)
@@ -38,6 +43,11 @@ function from_parent_dims(::Type{<:PermutedDimsArray{T,N,<:Any,I}}) where {T,N,I
     return _val_to_static(Val(I))
 end
 
+"""
+    to_parent_dims(::Type{T}) -> Bool
+
+Returns the mapping from child dimensions to parent dimensions.
+"""
 to_parent_dims(x) = to_parent_dims(typeof(x))
 to_parent_dims(::Type{T}) where {T} = nstatic(Val(ndims(T)))
 to_parent_dims(::Type{T}) where {T<:Union{Transpose,Adjoint}} = (StaticInt(2), One())

test/dimensions.jl

@@ -1,5 +1,28 @@
 @testset "dimensions" begin
 
+@testset "dimension permutations" begin
+    a = ones(2, 2, 2)
+    perm = PermutedDimsArray(a, (3, 1, 2))
+    mview = view(perm, :, 1, :)
+    madj = mview'
+    vview = view(madj, 1, :)
+    vadj = vview'
+
+    @test @inferred(ArrayInterface.to_parent_dims(typeof(a))) == (1, 2, 3)
+    @test @inferred(ArrayInterface.to_parent_dims(typeof(perm))) == (3, 1, 2)
+    @test @inferred(ArrayInterface.to_parent_dims(typeof(mview))) == (1, 3)
+    @test @inferred(ArrayInterface.to_parent_dims(typeof(madj))) == (2, 1)
+    @test @inferred(ArrayInterface.to_parent_dims(typeof(vview))) == (2,)
+    @test @inferred(ArrayInterface.to_parent_dims(typeof(vadj))) == (2, 1)
+
+    @test @inferred(ArrayInterface.from_parent_dims(typeof(a))) == (1, 2, 3)
+    @test @inferred(ArrayInterface.from_parent_dims(typeof(perm))) == (2, 3, 1)
+    @test @inferred(ArrayInterface.from_parent_dims(typeof(mview))) == (1, 0, 2)
+    @test @inferred(ArrayInterface.from_parent_dims(typeof(madj))) == (2, 1)
+    @test @inferred(ArrayInterface.from_parent_dims(typeof(vview))) == (0, 1)
+    @test @inferred(ArrayInterface.from_parent_dims(typeof(vadj))) == (2, 1)
+end
+
 @testset "to_dims" begin
     @testset "small case" begin
         @test ArrayInterface.to_dims((:x, :y), :x) == 1