optimize and fix map/broadcast over Adjoint/Transpose vectors

base/linalg/adjtrans.jl

@@ -136,30 +136,14 @@ hcat(tvs::Transpose{T,Vector{T}}...) where {T} = _transpose_hcat(tvs...)
 ### higher order functions
 # preserve Adjoint/Transpose wrapper around vectors
 # to retain the associated semantics post-map/broadcast
-
-# vectorfy takes an Adoint/Transpose-wrapped vector and builds
-# an unwrapped vector with the entrywise-same contents
-vectorfy(x::Number) = x
-vectorfy(adjvec::AdjointAbsVec) = map(Adjoint, adjvec.parent)
-vectorfy(transvec::TransposeAbsVec) = map(Transpose, transvec.parent)
-vectorfyall(transformedvecs...) = (map(vectorfy, transformedvecs)...,)
-
-# map over collections of Adjoint/Transpose-wrapped vectors
-# note that the caller's operation `f` should be applied to the entries of the wrapped
-# vectors, rather than the entires of the wrapped vector's parents. so first we use vectorfy
-# to build unwrapped vectors with entrywise-same contents as the wrapped input vectors.
-# then we map the caller's operation over that set of unwrapped vectors. but now re-wrapping
-# the resulting vector would inappropriately transform the result vector's entries. so
-# instead of simply mapping the caller's operation over the set of unwrapped vectors,
-# we map Adjoint/Transpose composed with the caller's operationt over the set of unwrapped
-# vectors. then re-wrapping the result vector yields a wrapped vector with the correct entries.
-map(f, avs::AdjointAbsVec...) = Adjoint(map(Adjoint∘f, vectorfyall(avs...)...))
-map(f, tvs::TransposeAbsVec...) = Transpose(map(Transpose∘f, vectorfyall(tvs...)...))
-
-# broadcast over collections of Adjoint/Transpose-wrapped vectors and numbers
-# similar explanation for these definitions as for map above
-broadcast(f, avs::Union{Number,AdjointAbsVec}...) = Adjoint(broadcast(Adjoint∘f, vectorfyall(avs...)...))
-broadcast(f, tvs::Union{Number,TransposeAbsVec}...) = Transpose(broadcast(Transpose∘f, vectorfyall(tvs...) ...))
+#
+# note that the caller's operation f operates in the domain of the wrapped vectors' entries.
+# hence the Adjoint->f->Adjoint shenanigans applied to the parent vectors' entries.
+map(f, avs::AdjointAbsVec...) = Adjoint(map((xs...) -> Adjoint(f(Adjoint.(xs)...)), parent.(avs)...))
+map(f, tvs::TransposeAbsVec...) = Transpose(map((xs...) -> Transpose(f(Transpose.(xs)...)), parent.(tvs)...))
+quasiparent(x) = parent(x); quasiparent(x::Number) = x # to handle numbers in the defs below
+broadcast(f, avs::Union{Number,AdjointAbsVec}...) = Adjoint(broadcast((xs...) -> Adjoint(f(Adjoint.(xs)...)), quasiparent.(avs)...))
+broadcast(f, tvs::Union{Number,TransposeAbsVec}...) = Transpose(broadcast((xs...) -> Transpose(f(Transpose.(xs)...)), quasiparent.(tvs)...))
 
 
 ### linear algebra

test/linalg/adjtrans.jl

@@ -338,6 +338,14 @@ end
     # trinary broadcast over wrapped vectors with concrete scalar eltype and numbers
     @test broadcast(+, Adjoint(vec), 1, Adjoint(vec))::Adjoint{Complex{Int},Vector{Complex{Int}}} == avec + avec .+ 1
     @test broadcast(+, Transpose(vec), 1, Transpose(vec))::Transpose{Complex{Int},Vector{Complex{Int}}} == tvec + tvec .+ 1
+    # ascertain inference friendliness, ref. https://github.com/JuliaLang/julia/pull/25083#issuecomment-353031641
+    sparsevec = SparseVector([1.0, 2.0, 3.0])
+    @test map(-, Adjoint(sparsevec), Adjoint(sparsevec)) isa Adjoint{Float64,SparseVector{Float64,Int}}
+    @test map(-, Transpose(sparsevec), Transpose(sparsevec)) isa Transpose{Float64,SparseVector{Float64,Int}}
+    @test broadcast(-, Adjoint(sparsevec), Adjoint(sparsevec)) isa Adjoint{Float64,SparseVector{Float64,Int}}
+    @test broadcast(-, Transpose(sparsevec), Transpose(sparsevec)) isa Transpose{Float64,SparseVector{Float64,Int}}
+    @test broadcast(+, Adjoint(sparsevec), 1.0, Adjoint(sparsevec)) isa Adjoint{Float64,SparseVector{Float64,Int}}
+    @test broadcast(+, Transpose(sparsevec), 1.0, Transpose(sparsevec)) isa Transpose{Float64,SparseVector{Float64,Int}}
 end
 
 @testset "Adjoint/Transpose-wrapped vector multiplication" begin