Merge pull request #135 from JuliaArrays/reshapereinterpretdensedims

Add dense_dims support for reinterpret(reshape, ...)

Author: chriselrod

Project.toml

@@ -1,6 +1,6 @@
 name = "ArrayInterface"
 uuid = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
-version = "3.1.5"
+version = "3.1.6"
 
 [deps]
 IfElse = "615f187c-cbe4-4ef1-ba3b-2fcf58d6d173"

src/stridelayout.jl

@@ -284,6 +284,12 @@ end
 function dense_dims(::Type{S}) where {N,NP,T,A<:AbstractArray{T,NP},I,S<:SubArray{T,N,A,I}}
     return _dense_dims(S, dense_dims(A), Val(stride_rank(A)))
 end
+if VERSION ≥ v"1.6.0-DEV.1581"
+    @inline function dense_dims(::Type{A}) where {NB, NA, B <: AbstractArray{<:Any,NB},A<: Base.ReinterpretArray{<:Any, NA, <:Any, B, true}}
+        ddb = dense_dims(B)
+        IfElse.ifelse(Static.le(StaticInt(NB), StaticInt(NA)), (True(), ddb...), Base.tail(ddb))                      
+    end
+end
 
 _dense_dims(::Type{S}, ::Nothing, ::Val{R}) where {R,N,NP,T,A<:AbstractArray{T,NP},I,S<:SubArray{T,N,A,I}} = nothing
 @generated function _dense_dims(

test/runtests.jl

@@ -468,10 +468,10 @@ end
     M = @MArray zeros(2,3,4); Mp = @view(PermutedDimsArray(M,(3,1,2))[:,2,:])';
     Sp2 = @view(PermutedDimsArray(S,(3,2,1))[2:3,:,:]);
     Mp2 = @view(PermutedDimsArray(M,(3,1,2))[2:3,:,2])';
-    D = @view(A[:,2:2:4,:])
-    R = StaticInt(1):StaticInt(2)
-    Rnr = reinterpret(Int32, R)
-    Ar = reinterpret(Float32, A)
+    D = @view(A[:,2:2:4,:]);
+    R = StaticInt(1):StaticInt(2);
+    Rnr = reinterpret(Int32, R);
+    Ar = reinterpret(Float32, A);
 
     sv5 = @SVector(zeros(5)); v5 = Vector{Float64}(undef, 5);
     @test @inferred(ArrayInterface.size(sv5)) === (StaticInt(5),)
@@ -611,15 +611,25 @@ end
 
         colormat = reinterpret(reshape, Float64, colors)
         @test @inferred(ArrayInterface.strides(colormat)) === (StaticInt(1), StaticInt(3))
-
+        @test @inferred(ArrayInterface.dense_dims(colormat)) === (True(),True())
+        @test @inferred(ArrayInterface.dense_dims(view(colormat,:,4))) === (True(),) 
+        @test @inferred(ArrayInterface.dense_dims(view(colormat,:,4:7))) === (True(),True())
+        @test @inferred(ArrayInterface.dense_dims(view(colormat,2:3,:))) === (True(),False())
+        
         Rr = reinterpret(reshape, Int32, R)
         @test @inferred(ArrayInterface.size(Rr)) === (StaticInt(2),StaticInt(2))
         @test @inferred(ArrayInterface.known_size(Rr)) === (2, 2)
 
+        
         Sr = Wrapper(reinterpret(reshape, Complex{Int64}, S))
         @test @inferred(ArrayInterface.size(Sr)) == (static(3), static(4))
         @test @inferred(ArrayInterface.known_size(Sr)) === (3, 4)
         @test @inferred(ArrayInterface.strides(Sr)) === (static(1), static(3))
+        Sr2 = reinterpret(reshape, Complex{Int64}, S);
+        @test @inferred(ArrayInterface.dense_dims(Sr2)) === (True(),True())
+        @test @inferred(ArrayInterface.dense_dims(view(Sr2,:,2))) === (True(),)
+        @test @inferred(ArrayInterface.dense_dims(view(Sr2,:,2:3))) === (True(),True())
+        @test @inferred(ArrayInterface.dense_dims(view(Sr2,2:3,:))) === (True(),False())
     end
 end