Specialize for Bidiagonal

Author: jishnub

src/bidiag.jl

@@ -115,6 +115,13 @@ Bidiagonal(A::Bidiagonal) = A
 Bidiagonal{T}(A::Bidiagonal{T}) where {T} = A
 Bidiagonal{T}(A::Bidiagonal) where {T} = Bidiagonal{T}(A.dv, A.ev, A.uplo)
 
+"""
+    LinearAlgebra.uplo(S::Bidiagonal)::Symbol
+
+Return a `Symbol` corresponding to whether the upper or lower off-diagonal band is stored.
+"""
+uplo(::Bidiagonal) = sym_uplo(B.uplo)
+
 _offdiagind(uplo) = uplo == 'U' ? 1 : -1
 
 @inline function Base.isassigned(A::Bidiagonal, i::Int, j::Int)

test/bidiag.jl

@@ -47,6 +47,8 @@ Random.seed!(1)
             # from vectors
             ubd = Bidiagonal(x, y, :U)
             lbd = Bidiagonal(x, y, :L)
+            @test LinearAlgebra.uplo(ubd) == :U
+            @test LinearAlgebra.uplo(lbd) == :L
             @test ubd != lbd || x === dv0
             @test ubd.dv === x
             @test lbd.ev === y