LinearAlgebra.givens with unitful arguments (#36430)

JuliaLang · Jul 3, 2020 · b79a6d1 · b79a6d1
1 parent f9496fb
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diff --git a/stdlib/LinearAlgebra/src/givens.jl b/stdlib/LinearAlgebra/src/givens.jl
@@ -46,6 +46,7 @@ end
 convert(::Type{T}, r::T) where {T<:AbstractRotation} = r
 convert(::Type{T}, r::AbstractRotation) where {T<:AbstractRotation} = T(r)
 
+Givens(i1, i2, c, s) = Givens(i1, i2, promote(c, s)...)
 Givens{T}(G::Givens{T}) where {T} = G
 Givens{T}(G::Givens) where {T} = Givens(G.i1, G.i2, convert(T, G.c), convert(T, G.s))
 Rotation{T}(R::Rotation{T}) where {T} = R
@@ -248,6 +249,18 @@ function givensAlgorithm(f::Complex{T}, g::Complex{T}) where T<:AbstractFloat
     return cs, sn, r
 end
 
+# enable for unitful quantities
+function givensAlgorithm(f::T, g::T) where T
+    fs = f / oneunit(T)
+    gs = g / oneunit(T)
+    typeof(fs) === T && typeof(gs) === T &&
+    !isa(fs, Union{AbstractFloat,Complex{<:AbstractFloat}}) &&
+    throw(MethodError(givensAlgorithm, (fs, gs)))
+
+    c, s, r = givensAlgorithm(fs, gs)
+    return c, s, r * oneunit(T)
+end
+
 givensAlgorithm(f, g) = givensAlgorithm(promote(float(f), float(g))...)
 
 """
@@ -280,7 +293,7 @@ function givens(f::T, g::T, i1::Integer, i2::Integer) where T
         s = -conj(s)
         i1,i2 = i2,i1
     end
-    Givens(i1, i2, convert(T, c), convert(T, s)), r
+    Givens(i1, i2, c, s), r
 end
 """
     givens(A::AbstractArray, i1::Integer, i2::Integer, j::Integer) -> (G::Givens, r)

diff --git a/stdlib/LinearAlgebra/test/givens.jl b/stdlib/LinearAlgebra/test/givens.jl
@@ -3,7 +3,7 @@
 module TestGivens
 
 using Test, LinearAlgebra, Random
-using LinearAlgebra: rmul!, lmul!
+using LinearAlgebra: rmul!, lmul!, Givens
 
 # Test givens rotations
 @testset for elty in (Float32, Float64, ComplexF32, ComplexF64)
@@ -70,4 +70,34 @@ using LinearAlgebra: rmul!, lmul!
     end
 end
 
+# 36430
+# dimensional correctness:
+const BASE_TEST_PATH = joinpath(Sys.BINDIR, "..", "share", "julia", "test")
+isdefined(Main, :Furlongs) || @eval Main include(joinpath($(BASE_TEST_PATH), "testhelpers", "Furlongs.jl"))
+using .Main.Furlongs
+
+@testset "testing dimensions with Furlongs" begin
+    @test_throws MethodError givens(Furlong(1.0), Furlong(2.0), 1, 2)
+end
+
+const TNumber = Union{Float64,ComplexF64}
+struct MockUnitful{T<:TNumber} <: Number
+    data::T
+    MockUnitful(data::T) where T<:TNumber = new{T}(data)
+end
+import Base: *, /, one, oneunit
+*(a::MockUnitful{T}, b::T) where T<:TNumber = MockUnitful(a.data * b)
+*(a::T, b::MockUnitful{T}) where T<:TNumber = MockUnitful(a * b.data)
+*(a::MockUnitful{T}, b::MockUnitful{T}) where T<:TNumber = MockUnitful(a.data * b.data)
+/(a::MockUnitful{T}, b::MockUnitful{T}) where T<:TNumber = a.data / b.data
+one(::Type{<:MockUnitful{T}}) where T = one(T)
+oneunit(::Type{<:MockUnitful{T}}) where T = MockUnitful(one(T))
+
+@testset "unitful givens rotation unitful $T " for T in (Float64, ComplexF64)
+    g, r = givens(MockUnitful(T(3)), MockUnitful(T(4)), 1, 2)
+    @test g.c ≈ 3/5
+    @test g.s ≈ 4/5
+    @test r.data ≈ 5.0
+end
+
 end # module TestGivens