Support array eltypes in zeroeltype for Mul getindex

Project.toml

@@ -1,6 +1,6 @@
 name = "ArrayLayouts"
 uuid = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
-version = "1.12.3"
+version = "1.12.4"
 authors = ["Sheehan Olver <solver@mac.com>"]
 
 [deps]

src/mul.jl

@@ -31,7 +31,10 @@ axes(M::Mul) = _mul_axes(axes(M.A), axes(M.B))
 # The following design is to support QuasiArrays.jl where indices
 # may not be `Int`
 
-zeroeltype(M) = zero(eltype(M)) # allow special casing where we know more about zero
+zeroeltype(M) = _zeroeltype(eltype(M), M) # allow special casing where we know more about zero
+_zeroeltype(::Type{T}, M) where T = zero(T)
+# zero(T) is not defined for arrays like Vector{Float64} so use the entries to determine the size
+_zeroeltype(::Type{T}, M::Mul) where T<:AbstractArray = convert(T, zero(first(M.A) * first(M.B)))
 zeroeltype(M::Mul{<:Any,<:Any,<:SubArray}) = zeroeltype(Mul(parent(M.A), M.B))
 
 function _getindex(::Type{Tuple{AA}}, M::Mul, (k,)::Tuple{AA}) where AA

test/test_muladd.jl

@@ -92,6 +92,15 @@ Random.seed!(0)
             @test mul(X,A) == X*A
         end
 
+        @testset "Mul getindex with array eltype" begin
+            X = reshape([[1 2; 3 4], [5 6; 7 8]], 1, 2)
+            c = [1, 2]
+            @test ArrayLayouts.Mul(X, c)[1] == X[1] + 2X[2]
+            @test ArrayLayouts.Mul(X, reshape(c,2,1))[1,1] == X[1] + 2X[2]
+            v = reshape([[1.0, 2.0], [3.0, 4.0]], 1, 2)
+            @test ArrayLayouts.Mul(v, c)[1] == [7.0, 10.0]
+        end
+
         @testset "Diagonal Fill" begin
             for (A, B) in (([1:4;], [3:6;]), (reshape([1:16;],4,4), reshape(2 .* [1:16;],4,4)))
                 D = Diagonal(Fill(3, 4))