row/colsupport for QRPackedQ and adjoint (#227)

* row/colsupport for QRPackedQ and adjoint

* Update test_ldiv.jl

Author: dlfivefifty

Project.toml

@@ -1,7 +1,7 @@
 name = "ArrayLayouts"
 uuid = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
 authors = ["Sheehan Olver <[email protected]>"]
-version = "1.9.1"
+version = "1.9.2"
 
 [deps]
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"

src/factorizations.jl

@@ -122,6 +122,12 @@ MemoryLayout(::Type{<:LinearAlgebra.QRCompactWYQ{<:Any,S}}) where {S} =
 adjointlayout(::Type, ::QRPackedQLayout{SLAY,TLAY}) where {SLAY,TLAY} = AdjQRPackedQLayout{SLAY,TLAY}()
 adjointlayout(::Type, ::QRCompactWYQLayout{SLAY,TLAY}) where {SLAY,TLAY} = AdjQRCompactWYQLayout{SLAY,TLAY}()
 
+colsupport(::QRPackedQLayout, Q, j) = oneto(maximum(colsupport(Q.factors, j)))
+rowsupport(::QRPackedQLayout, Q, k) = minimum(rowsupport(Q.factors, k)):size(Q,2)
+colsupport(::AdjQRPackedQLayout, Q, j) = minimum(colsupport(Q'.factors, j)):size(Q,1)
+rowsupport(::AdjQRPackedQLayout, Q, k) = oneto(maximum(rowsupport(Q'.factors, k)))
+
+
 copy(M::Lmul{<:AbstractQLayout}) = copyto!(similar(M), M)
 mulreduce(M::Mul{<:AbstractQLayout,<:AbstractQLayout}) = Lmul(M)
 mulreduce(M::Mul{<:AbstractQLayout}) = Lmul(M)

test/test_ldiv.jl

@@ -258,6 +258,15 @@ import ArrayLayouts: ApplyBroadcastStyle, QRCompactWYQLayout, QRCompactWYLayout,
                 @test ArrayLayouts.ldiv!(F, v) === v
                 @test ArrayLayouts.ldiv!(F, view(copy(b),:)) ≈ A \ b
             end
+
+            @testset "row/colsupport" begin
+                n = 10
+                B = Bidiagonal(randn(n), randn(n-1), :L)
+                Q = LinearAlgebra.qrfactUnblocked!(Matrix(B))
+                Q = LinearAlgebra.QRPackedQ(Tridiagonal(Q.factors), Q.τ)
+                @test rowsupport(Q, 4) ≡ colsupport(Q', 4) ≡ 3:10
+                @test colsupport(Q, 4) ≡ rowsupport(Q', 4) ≡ Base.OneTo(5)
+            end
         end
     end