Merge pull request #941 from thchr/float-real-satype

implement `float` and `real` for `StaticArray` (fix #935)

Author: andyferris

src/StaticArrays.jl

@@ -13,7 +13,7 @@ import Statistics: mean
 using Random
 import Random: rand, randn, randexp, rand!, randn!, randexp!
 using Core.Compiler: return_type
-import Base: sqrt, exp, log
+import Base: sqrt, exp, log, float, real
 using LinearAlgebra
 import LinearAlgebra: transpose, adjoint, dot, eigvals, eigen, lyap, tr,
                       kron, diag, norm, dot, diagm, lu, svd, svdvals,

src/convert.jl

@@ -47,3 +47,7 @@ length_val(a::Type{T}) where {T<:StaticArrayLike} = length_val(Size(T))
         @inbounds return $(Expr(:tuple, exprs...))
     end
 end
+
+# `float` and `real` of StaticArray types, analogously to application to scalars (issue 935)
+float(::Type{SA}) where SA<:StaticArray{_S,T,_N} where {_S,T,_N} = similar_type(SA, float(T))
+real(::Type{SA}) where SA<:StaticArray{_S,T,_N} where {_S,T,_N} = similar_type(SA, real(T))

test/convert.jl

@@ -19,3 +19,26 @@ end # testset
     @test Scalar{Int}[SVector{1,Int}(3), SVector{1,Float64}(2.0)] == [Scalar{Int}(3), Scalar{Int}(2)]
     @test Scalar[SVector{1,Int}(3), SVector{1,Float64}(2.0)] == [Scalar{Int}(3), Scalar{Float64}(2.0)]
 end
+
+@testset "`real` and `float` of SArray/MArray" begin
+    # Issue 935
+    for SAT in (SArray, MArray)
+        vInt = SAT(SA[1,2,3])           # S/MVector{3, Int}
+        @test real(typeof(vInt)) === typeof(vInt)
+        @test float(typeof(vInt)) === typeof(float.(vInt))
+
+        vCInt = vInt + 1im*vInt         # S/MVector{3, Complex{Int}}
+        @test real(typeof(vCInt)) === typeof(vInt)
+        @test float(typeof(vCInt)) === typeof(float.(vCInt))
+        
+        vvInt = SAT(SA[vInt, vInt])    # S/MVector{2, S/MVector{3, Int}}
+        @test real(typeof(vvInt)) === SAT{Tuple{2}, SAT{Tuple{3}, Int, 1, 3}, 1, 2}
+        @test float(typeof(vvInt)) === SAT{Tuple{2}, SAT{Tuple{3}, Float64, 1, 3}, 1, 2}
+
+        vvCInt = SAT(SA[vCInt, vCInt]) # S/MVector{2, S/MVector{3, Complex{Int}}}
+        @test real(typeof(vvCInt)) === SAT{Tuple{2}, SAT{Tuple{3}, Int, 1, 3}, 1, 2}
+        @test float(typeof(vvCInt)) === SAT{Tuple{2}, SAT{Tuple{3}, Complex{Float64}, 1, 3}, 1, 2}
+    end
+    mInt = SA[Int16(1) Int16(2) Int16(3); Int16(4) Int16(5) Int16(6)] # SMatrix{3,2,Int16}
+    @test float(typeof(mInt)) === SMatrix{2, 3, float(Int16), 6}
+end