Structured Broadcasting (#228)

* Structured Broadcasting

* add jishnubs tests

* Update runtests.jl

Project.toml

@@ -9,7 +9,7 @@ SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [compat]
-Aqua = "0.5"
+Aqua = "0.5, 0.6"
 julia = "1.6"
 
 [extras]

src/fillbroadcast.jl

@@ -247,3 +247,8 @@ broadcasted(::DefaultArrayStyle{N}, ::typeof(Base.literal_pow), ::Base.RefValue{
 broadcasted(::DefaultArrayStyle{N}, ::typeof(Base.literal_pow), ::Base.RefValue{typeof(^)}, r::Ones{T,N}, ::Base.RefValue{Val{k}}) where {T,N,k} = Ones{T}(axes(r))
 broadcasted(::DefaultArrayStyle{N}, ::typeof(Base.literal_pow), ::Base.RefValue{typeof(^)}, r::Zeros{T,N}, ::Base.RefValue{Val{0}}) where {T,N} = Ones{T}(axes(r))
 broadcasted(::DefaultArrayStyle{N}, ::typeof(Base.literal_pow), ::Base.RefValue{typeof(^)}, r::Zeros{T,N}, ::Base.RefValue{Val{k}}) where {T,N,k} = Zeros{T}(axes(r))
+
+# supports structured broadcast
+if isdefined(LinearAlgebra, :fzero)
+    LinearAlgebra.fzero(x::Zeros) = zero(eltype(x))
+end

test/runtests.jl

@@ -1471,3 +1471,19 @@ end
     @test cor(Fill(3, 4, 5)) ≈ cor(fill(3, 4, 5)) nans=true
     @test cor(Fill(3, 4, 5), dims=2) ≈ cor(fill(3, 4, 5), dims=2) nans=true
 end
+
+@testset "Structured broadcast" begin
+    D = Diagonal(1:5)
+    @test D + Zeros(5,5) isa Diagonal
+    @test D - Zeros(5,5) isa Diagonal
+    @test D .+ Zeros(5,5) isa Diagonal
+    @test D .- Zeros(5,5) isa Diagonal
+    @test D .* Zeros(5,5) isa Diagonal
+    @test Zeros(5,5) .* D isa Diagonal
+    @test Zeros(5,5) - D isa Diagonal
+    @test Zeros(5,5) + D isa Diagonal
+    @test Zeros(5,5) .- D isa Diagonal
+    @test Zeros(5,5) .+ D isa Diagonal
+    f = (x,y) -> x+1
+    @test f.(D, Zeros(5,5)) isa Matrix
+end