Add eltype for Dot (#34)

Author: dlfivefifty

Project.toml

@@ -1,7 +1,7 @@
 name = "ArrayLayouts"
 uuid = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
 authors = ["Sheehan Olver <[email protected]>"]
-version = "0.4.1"
+version = "0.4.2"
 
 [deps]
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"

src/mul.jl

@@ -233,6 +233,7 @@ end
 @inline materialize(d::Dot) = copy(instantiate(d))
 @inline Dot(M::Mul{<:DualLayout,<:Any,<:AbstractMatrix,<:AbstractVector}) = Dot(M.A', M.B)
 @inline mulreduce(M::Mul{<:DualLayout,<:Any,<:AbstractMatrix,<:AbstractVector}) = Dot(M)
+@inline eltype(D::Dot) = promote_type(eltype(D.A), eltype(D.B))
 
 dot(a, b) = materialize(Dot(a, b))
 @inline LinearAlgebra.dot(a::LayoutArray, b::LayoutArray) = dot(a,b)

test/test_muladd.jl

@@ -636,5 +636,6 @@ Random.seed!(0)
         a = randn(5)
         b = randn(5)
         @test ArrayLayouts.dot(a,b) == mul(a',b) == dot(a,b)
+        @test eltype(Dot(a,1:5)) == Float64
     end
 end