Revert "add missing methods for division of Hessenberg matrices (#1322)"

This reverts commit 6d36322.

Author: jishnub

src/hessenberg.jl

@@ -177,29 +177,6 @@ function \(U::UnitUpperTriangular, H::UpperHessenberg)
     UpperHessenberg(HH)
 end
 
-function (\)(H::Union{UpperHessenberg,AdjOrTrans{<:Any,<:UpperHessenberg}}, B::AbstractVecOrMat)
-    TFB = typeof(oneunit(eltype(H)) \ oneunit(eltype(B)))
-    return ldiv!(H, copy_similar(B, TFB))
-end
-
-function (/)(B::AbstractMatrix, H::Union{UpperHessenberg,AdjOrTrans{<:Any,<:UpperHessenberg}})
-    TFB = typeof(oneunit(eltype(B)) / oneunit(eltype(H)))
-    return rdiv!(copy_similar(B, TFB), H)
-end
-
-ldiv!(H::AdjOrTrans{<:Any,<:UpperHessenberg}, B::AbstractVecOrMat) =
-    (rdiv!(wrapperop(H)(B), parent(H)); B)
-rdiv!(B::AbstractVecOrMat, H::AdjOrTrans{<:Any,<:UpperHessenberg}) =
-    (ldiv!(parent(H), wrapperop(H)(B)); B)
-
-# fix method ambiguities for right division, from adjtrans.jl:
-/(u::AdjointAbsVec, A::UpperHessenberg) = adjoint(adjoint(A) \ u.parent)
-/(u::TransposeAbsVec, A::UpperHessenberg) = transpose(transpose(A) \ u.parent)
-/(u::AdjointAbsVec, A::Adjoint{<:Any,<:UpperHessenberg}) = adjoint(adjoint(A) \ u.parent)
-/(u::TransposeAbsVec, A::Transpose{<:Any,<:UpperHessenberg}) = transpose(transpose(A) \ u.parent)
-/(u::AdjointAbsVec, A::Transpose{<:Any,<:UpperHessenberg}) = adjoint(conj(A.parent) \ u.parent) # technically should be adjoint(copy(adjoint(copy(A))) \ u.parent)
-/(u::TransposeAbsVec, A::Adjoint{<:Any,<:UpperHessenberg}) = transpose(conj(A.parent) \ u.parent)
-
 # Solving (H+µI)x = b: we can do this in O(m²) time and O(m) memory
 # (in-place in x) by the RQ algorithm from:
 #

test/hessenberg.jl

@@ -64,13 +64,6 @@ let n = 10
         H = UpperHessenberg(Areal)
         @test Array(Hc + H) == Array(Hc) + Array(H)
         @test Array(Hc - H) == Array(Hc) - Array(H)
-        @testset "ldiv and rdiv" begin
-            for b in (b_, B_), H in (H, Hc, H', Hc', transpose(Hc))
-                @test H * (H \ b) ≈ b
-                @test (b' / H) * H ≈ (Matrix(b') / H) * H ≈ b'
-                @test (transpose(b) / H) * H ≈ (Matrix(transpose(b)) / H) * H ≈ transpose(b)
-            end
-        end
         @testset "Preserve UpperHessenberg shape (issue #39388)" begin
             H = UpperHessenberg(Areal)
             A = rand(n,n)