Fix some ambiguities between BandedLazyLayouts and LazyLayouts (#324)

* Fix some ambiguities

* add pr number

* Fix simplifiable ambiguities

* Undo simplifiable changes

Author: DanielVandH

Project.toml

@@ -1,6 +1,6 @@
 name = "LazyArrays"
 uuid = "5078a376-72f3-5289-bfd5-ec5146d43c02"
-version = "2.1"
+version = "2.1.1"
 
 [deps]
 ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"

ext/LazyArraysBandedMatricesExt.jl

@@ -584,6 +584,7 @@ copy(M::Mul{<:AbstractInvLayout, <:BandedLazyLayouts}) = simplify(M)
 
 
 copy(L::Ldiv{<:BandedLazyLayouts}) = lazymaterialize(\, L.A, L.B)
+copy(L::Ldiv{<:BandedLazyLayouts,<:AbstractLazyLayout}) = lazymaterialize(\, L.A, L.B)
 copy(L::Ldiv{<:BandedLazyLayouts, Blay}) where Blay<:Union{AbstractStridedLayout,PaddedColumns} = copy(Ldiv{UnknownLayout,Blay}(L.A, L.B))
 
 ## The following needs more thought but for now it fixes a bug downstream.
@@ -630,6 +631,7 @@ simplifiable(M::Mul{<:BandedLazyLayouts, <:Union{AbstractPaddedLayout,AbstractSt
 simplifiable(::Mul{<:BroadcastBandedLayout, <:Union{AbstractPaddedLayout,AbstractStridedLayout}}) = Val(true)
 
 copy(L::Ldiv{ApplyBandedLayout{typeof(*)}, Lay}) where Lay = copy(Ldiv{ApplyLayout{typeof(*)},Lay}(L.A, L.B))
+copy(L::Ldiv{ApplyBandedLayout{typeof(*)}, Lay}) where {Lay<:AbstractLazyLayout} = copy(Ldiv{ApplyLayout{typeof(*)},Lay}(L.A, L.B))
 copy(L::Ldiv{ApplyBandedLayout{typeof(*)}, Lay}) where Lay<:BroadcastBandedLayout = copy(Ldiv{ApplyLayout{typeof(*)},Lay}(L.A, L.B))
 copy(L::Ldiv{ApplyBandedLayout{typeof(*)}, Lay}) where Lay<:Union{PaddedColumns,AbstractStridedLayout} = copy(Ldiv{ApplyLayout{typeof(*)},Lay}(L.A, L.B))
 inv_layout(::BandedLazyLayouts, _, A) = ApplyArray(inv, A)

test/bandedtests.jl

@@ -871,6 +871,15 @@ LinearAlgebra.lmul!(β::Number, A::PseudoBandedMatrix) = (lmul!(β, A.data); A)
         B = Bidiagonal(a, b, :U)
         @test ldiv(B, Diagonal(1:n)) ≈ ApplyArray(inv,B) * Diagonal(1:n) ≈ B \ Diagonal(1:n)
     end
+    
+    @testset "Ambiguity between ldiv(BandedLazy, Lazy) and ldiv(ApplyBandedLazy, Lazy) (#324)" begin
+        A = ApplyArray(*, brand(5, 2, 3), brand(5, 2, 3))
+        B = ApplyArray(inv, rand(5, 5))
+        @test A \ B ≈ Matrix(A) \ Matrix(B)
+
+        A = Bidiagonal(ApplyVector(+, 1:5, 1:5), ApplyVector(+, 1:4, 1:4), 'U')
+        @test A \ B ≈ Matrix(A) \ Matrix(B)
+    end
 end
 
 end # module