# This file is a part of Julia. License is MIT: https://julialang.org/license

module TestSymmetric

using Test, LinearAlgebra, Random

const BASE_TEST_PATH = joinpath(Sys.BINDIR, "..", "share", "julia", "test")

isdefined(Main, :Quaternions) || @eval Main include(joinpath($(BASE_TEST_PATH), "testhelpers", "Quaternions.jl"))
using .Main.Quaternions

isdefined(Main, :SizedArrays) || @eval Main include(joinpath($(BASE_TEST_PATH), "testhelpers", "SizedArrays.jl"))
using .Main.SizedArrays

Random.seed!(1010)

@testset "Pauli σ-matrices: $σ" for σ in map(Hermitian,
        Any[ [1 0; 0 1], [0 1; 1 0], [0 -im; im 0], [1 0; 0 -1] ])
    @test ishermitian(σ)
end

@testset "Two-dimensional Euler formula for Hermitian" begin
    @test cis(Hermitian([π 0; 0 π])) ≈ -I
end

@testset "Hermitian matrix exponential/log" begin
    A1 = randn(4,4) + im*randn(4,4)
    A2 = A1 + A1'
    @test exp(A2) ≈ exp(Hermitian(A2))
    @test cis(A2) ≈ cis(Hermitian(A2))
    @test log(A2) ≈ log(Hermitian(A2))
    A3 = A1 * A1' # posdef
    @test exp(A3) ≈ exp(Hermitian(A3))
    @test cis(A3) ≈ cis(Hermitian(A3))
    @test log(A3) ≈ log(Hermitian(A3))

    A1 = randn(4,4)
    A3 = A1 * A1'
    A4 = A1 + transpose(A1)
    @test exp(A4) ≈ exp(Symmetric(A4))
    @test log(A3) ≈ log(Symmetric(A3))
    @test log(A3) ≈ log(Hermitian(A3))
end

@testset "Core functionality" begin
    n = 10
    areal = randn(n,n)/2
    aimg  = randn(n,n)/2
    @testset for eltya in (Float32, Float64, ComplexF32, ComplexF64, BigFloat, Int)
        a = eltya == Int ? rand(1:7, n, n) : convert(Matrix{eltya}, eltya <: Complex ? complex.(areal, aimg) : areal)
        asym = transpose(a) + a                 # symmetric indefinite
        aherm = a' + a                 # Hermitian indefinite
        apos  = a' * a                 # Hermitian positive definite
        aposs = apos + transpose(apos)        # Symmetric positive definite
        ε = εa = eps(abs(float(one(eltya))))

        x = randn(n)
        y = randn(n)
        b = randn(n,n)/2
        x = eltya == Int ? rand(1:7, n) : convert(Vector{eltya}, eltya <: Complex ? complex.(x, zeros(n)) : x)
        y = eltya == Int ? rand(1:7, n) : convert(Vector{eltya}, eltya <: Complex ? complex.(y, zeros(n)) : y)
        b = eltya == Int ? rand(1:7, n, n) : convert(Matrix{eltya}, eltya <: Complex ? complex.(b, zeros(n,n)) : b)
        @testset "basic ops" begin
            @testset "constructor" begin
                @test Symmetric(Symmetric(asym, :U))     === Symmetric(asym, :U)
                @test Hermitian(Hermitian(aherm, :U))    === Hermitian(aherm, :U)
                @test Symmetric(Symmetric(asym, :U), :U) === Symmetric(asym, :U)
                @test Hermitian(Hermitian(aherm, :U), :U) === Hermitian(aherm, :U)
                @test_throws ArgumentError Symmetric(Symmetric(asym, :U), :L)
                @test_throws ArgumentError Hermitian(Hermitian(aherm, :U), :L)

                @test_throws ArgumentError Symmetric(asym, :R)
                @test_throws ArgumentError Hermitian(asym, :R)

                @test_throws MethodError Symmetric{eltya,typeof(asym)}(asym, :L)
                @test_throws MethodError Hermitian{eltya,typeof(aherm)}(aherm, :L)

                # mixed cases with Hermitian/Symmetric
                if eltya <: Real
                    @test Symmetric(Hermitian(aherm, :U))     === Symmetric(aherm, :U)
                    @test Hermitian(Symmetric(asym, :U))     === Hermitian(asym, :U)
                    @test Symmetric(Hermitian(aherm, :U), :U) === Symmetric(aherm, :U)
                    @test Hermitian(Symmetric(asym, :U), :U) === Hermitian(asym, :U)
                    @test_throws ArgumentError Symmetric(Hermitian(aherm, :U), :L)
                    @test_throws ArgumentError Hermitian(Symmetric(aherm, :U), :L)
                end
            end
            @testset "diag" begin
                D = Diagonal(x)
                DM = Matrix(D)
                B = diagm(-1 => x, 1 => x)
                for uplo in (:U, :L)
                    @test diag(Symmetric(D, uplo))::Vector == x
                    @test diag(Hermitian(D, uplo))::Vector == real(x)
                    @test isdiag(Symmetric(DM, uplo))
                    @test isdiag(Hermitian(DM, uplo))
                    @test !isdiag(Symmetric(B, uplo))
                    @test !isdiag(Hermitian(B, uplo))
                end
            end
            @testset "similar" begin
                @test isa(similar(Symmetric(asym)), Symmetric{eltya})
                @test isa(similar(Hermitian(aherm)), Hermitian{eltya})
                @test isa(similar(Symmetric(asym), Int), Symmetric{Int})
                @test isa(similar(Hermitian(aherm), Int), Hermitian{Int})
                @test isa(similar(Symmetric(asym), (3,2)), Matrix{eltya})
                @test isa(similar(Hermitian(aherm), (3,2)), Matrix{eltya})
                @test isa(similar(Symmetric(asym), Int, (3,2)), Matrix{Int})
                @test isa(similar(Hermitian(aherm), Int, (3,2)), Matrix{Int})
            end

            @testset "Array/Matrix constructor from Symmetric/Hermitian" begin
                @test asym  == Matrix(Symmetric(asym))  == Array(Symmetric(asym))
                @test aherm == Matrix(Hermitian(aherm)) == Array(Hermitian(aherm))
            end

            @testset "parent" begin
                @test asym === parent(Symmetric(asym))
                @test aherm === parent(Hermitian(aherm))
            end
            # Unary minus for Symmetric/Hermitian matrices
            @testset "Unary minus for Symmetric/Hermitian matrices" begin
                @test (-Symmetric(asym))::typeof(Symmetric(asym)) == -asym
                @test (-Hermitian(aherm))::typeof(Hermitian(aherm)) == -aherm
                @test (-Symmetric([true true; false false]))::Symmetric{Int,Matrix{Int}} == [-1 -1; -1 0]
                @test (-Hermitian([true false; true false]))::Hermitian{Int,Matrix{Int}} == [-1 0; 0 0]
            end

            @testset "Addition and subtraction for Symmetric/Hermitian matrices" begin
                for f in (+, -)
                    @test (f(Symmetric(asym), Symmetric(aposs)))::typeof(Symmetric(asym)) == f(asym, aposs)
                    @test (f(Hermitian(aherm), Hermitian(apos)))::typeof(Hermitian(aherm)) == f(aherm, apos)
                    @test (f(Symmetric(real(asym)), Hermitian(aherm)))::typeof(Hermitian(aherm)) == f(real(asym), aherm)
                    @test (f(Hermitian(aherm), Symmetric(real(asym))))::typeof(Hermitian(aherm)) == f(aherm, real(asym))
                    @test (f(Symmetric(asym), Hermitian(aherm))) == f(asym, aherm)
                    @test (f(Hermitian(aherm), Symmetric(asym))) == f(aherm, asym)
                end
            end

            @testset "getindex and unsafe_getindex" begin
                @test aherm[1,1] == Hermitian(aherm)[1,1]
                @test asym[1,1] == Symmetric(asym)[1,1]
                @test Symmetric(asym)[1:2,1:2] == asym[1:2,1:2]
                @test Hermitian(aherm)[1:2,1:2] == aherm[1:2,1:2]
            end

            @testset "conversion" begin
                @test Symmetric(asym) == convert(Symmetric,Symmetric(asym))
                if eltya <: Real
                    typs = [Float16,Float32,Float64]
                    for typ in typs
                        @test Symmetric(convert(Matrix{typ},asym)) == convert(Symmetric{typ,Matrix{typ}},Symmetric(asym))
                    end
                end
                if eltya <: Complex
                    typs = [ComplexF32,ComplexF64]
                    for typ in typs
                        @test Symmetric(convert(Matrix{typ},asym)) == convert(Symmetric{typ,Matrix{typ}},Symmetric(asym))
                        @test Hermitian(convert(Matrix{typ},aherm)) == convert(Hermitian{typ,Matrix{typ}},Hermitian(aherm))
                    end
                end
                @test Symmetric{eltya, Matrix{eltya}}(Symmetric(asym, :U)) === Symmetric(asym, :U)
                @test Hermitian{eltya, Matrix{eltya}}(Hermitian(aherm, :U)) === Hermitian(aherm, :U)
            end

            @testset "issymmetric, ishermitian" begin
                @test issymmetric(Symmetric(asym))
                @test ishermitian(Hermitian(aherm))
                if eltya <: Real
                    @test ishermitian(Symmetric(asym))
                    @test issymmetric(Hermitian(asym))
                elseif eltya <: Complex
                    # test that zero imaginary component is
                    # handled properly
                    @test ishermitian(Symmetric(b + b'))
                end
            end

            @testset "tril/triu" begin
                for (op, validks) in (
                        (triu, (-n + 1):(n + 1)),
                        (tril, (-n - 1):(n - 1)) )
                    for di in validks
                        @test op(Symmetric(asym), di) == op(asym, di)
                        @test op(Hermitian(aherm), di) == op(aherm, di)
                        @test op(Symmetric(asym, :L), di) == op(asym, di)
                        @test op(Hermitian(aherm, :L), di) == op(aherm, di)
                    end
                end
            end

            @testset "transpose, adjoint" begin
                S = Symmetric(asym)
                H = Hermitian(aherm)
                @test transpose(S) === S == asym
                @test adjoint(H) === H == aherm
                if eltya <: Real
                    @test adjoint(S) === S == asym
                    @test  transpose(H) === H == aherm
                else
                    @test adjoint(S) ==  Symmetric(conj(asym))
                    @test transpose(H) ==  Hermitian(copy(transpose(aherm)))
                end
                @test copy(adjoint(H)) == copy(aherm)
                @test copy(transpose(S)) == copy(asym)
            end

            @testset "real, imag" begin
                S = Symmetric(asym)
                H = Hermitian(aherm)
                @test issymmetric(real(S))
                @test ishermitian(real(H))
                if eltya <: Real
                    @test real(S) === S == asym
                    @test real(H) === H == aherm
                elseif eltya <: Complex
                    @test issymmetric(imag(S))
                    @test !ishermitian(imag(H))
                end
            end

        end

        @testset "linalg unary ops" begin
            @testset "tr" begin
                @test tr(asym) ≈ tr(Symmetric(asym))
                @test tr(aherm) ≈ tr(Hermitian(aherm))
            end

            @testset "isposdef[!]" begin
                @test isposdef(Symmetric(asym))  == isposdef(asym)
                @test isposdef(Symmetric(aposs)) == isposdef(aposs) == true
                @test isposdef(Hermitian(aherm)) == isposdef(aherm)
                @test isposdef(Hermitian(apos))  == isposdef(apos) == true
                if eltya != Int #chol! won't work with Int
                    @test isposdef!(Symmetric(copy(asym)))  == isposdef(asym)
                    @test isposdef!(Symmetric(copy(aposs))) == isposdef(aposs) == true
                    @test isposdef!(Hermitian(copy(aherm))) == isposdef(aherm)
                    @test isposdef!(Hermitian(copy(apos)))  == isposdef(apos) == true
                end
            end

            @testset "$f" for f in (det, logdet, logabsdet)
                for uplo in (:U, :L)
                    @test all(f(apos)  .≈ f(Hermitian(apos, uplo)))
                    @test all(f(aposs) .≈ f(Symmetric(aposs, uplo)))
                    if f != logdet
                        @test all(f(aherm) .≈ f(Hermitian(aherm, uplo)))
                        @test all(f(asym)  .≈ f(Symmetric(asym, uplo)))
                    end
                end
            end

            @testset "inversion" begin
                for uplo in (:U, :L)
                    @test inv(Symmetric(asym, uplo))::Symmetric ≈ inv(asym)
                    @test inv(Hermitian(aherm, uplo))::Hermitian ≈ inv(aherm)
                    @test inv(Symmetric(a, uplo))::Symmetric ≈ inv(Matrix(Symmetric(a, uplo)))
                    if eltya <: Real
                        @test inv(Hermitian(a, uplo))::Hermitian ≈ inv(Matrix(Hermitian(a, uplo)))
                    end
                end
                if eltya <: LinearAlgebra.BlasComplex
                    @testset "inverse edge case with complex Hermitian" begin
                        # Hermitian matrix, where inv(lu(A)) generates non-real diagonal elements
                        for T in (ComplexF32, ComplexF64)
                            # data should have nonvanishing imaginary parts on the diagonal
                            M = T[0.279982+0.988074im  0.770011+0.870555im
                                    0.138001+0.889728im  0.177242+0.701413im]
                            H = Hermitian(M)
                            A = Matrix(H)
                            @test inv(H) ≈ inv(A)
                            @test ishermitian(Matrix(inv(H)))
                        end
                    end
                end
                if eltya <: AbstractFloat
                @testset "inv should error with NaNs/Infs" begin
                    h = Hermitian(fill(eltya(NaN), 2, 2))
                    @test_throws ArgumentError inv(h)
                    s = Symmetric(fill(eltya(NaN), 2, 2))
                    @test_throws ArgumentError inv(s)
                end
                end
            end

            # Revisit when implemented in julia
            if eltya != BigFloat
                @testset "cond" begin
                    if eltya <: Real #svdvals! has no method for Symmetric{Complex}
                        @test cond(Symmetric(asym)) ≈ cond(asym)
                    end
                    @test cond(Hermitian(aherm)) ≈ cond(aherm)
                end

                @testset "symmetric eigendecomposition" begin
                    if eltya <: Real # the eigenvalues are only real and ordered for Hermitian matrices
                        d, v = eigen(asym)
                        @test asym*v[:,1] ≈ d[1]*v[:,1]
                        @test v*Diagonal(d)*transpose(v) ≈ asym
                        @test isequal(eigvals(asym[1]), eigvals(asym[1:1,1:1])[1])
                        @test abs.(eigen(Symmetric(asym), 1:2).vectors'v[:,1:2]) ≈ Matrix(I, 2, 2)
                        @test abs.(eigen(Symmetric(asym), d[1] - 1, (d[2] + d[3])/2).vectors'v[:,1:2]) ≈ Matrix(I, 2, 2)
                        @test eigvals(Symmetric(asym), 1:2) ≈ d[1:2]
                        @test eigvals(Symmetric(asym), sortby= x -> -x) ≈ eigvals(eigen(Symmetric(asym), sortby = x -> -x))
                        @test eigvals(Symmetric(asym), d[1] - 1, (d[2] + d[3])/2) ≈ d[1:2]
                        # eigen doesn't support Symmetric{Complex}
                        @test Matrix(eigen(asym)) ≈ asym
                        @test eigvecs(Symmetric(asym)) ≈ eigvecs(asym)
                    end

                    d, v = eigen(aherm)
                    @test aherm*v[:,1] ≈ d[1]*v[:,1]
                    @test v*Diagonal(d)*v' ≈ aherm
                    @test isequal(eigvals(aherm[1]), eigvals(aherm[1:1,1:1])[1])
                    @test abs.(eigen(Hermitian(aherm), 1:2).vectors'v[:,1:2]) ≈ Matrix(I, 2, 2)
                    @test abs.(eigen(Hermitian(aherm), d[1] - 1, (d[2] + d[3])/2).vectors'v[:,1:2]) ≈ Matrix(I, 2, 2)
                    @test eigvals(Hermitian(aherm), 1:2) ≈ d[1:2]
                    @test eigvals(Hermitian(aherm), sortby= x -> -x) ≈ eigvals(eigen(Hermitian(aherm), sortby = x -> -x))
                    @test eigvals(Hermitian(aherm), d[1] - 1, (d[2] + d[3])/2) ≈ d[1:2]
                    @test Matrix(eigen(aherm)) ≈ aherm
                    @test eigvecs(Hermitian(aherm)) ≈ eigvecs(aherm)

                    # relation to svdvals
                    if eltya <: Real #svdvals! has no method for Symmetric{Complex}
                        @test sum(sort(abs.(eigvals(Symmetric(asym))))) == sum(sort(svdvals(Symmetric(asym))))
                    end
                    @test sum(sort(abs.(eigvals(Hermitian(aherm))))) == sum(sort(svdvals(Hermitian(aherm))))
                end

                @testset "rank" begin
                    let A = a[:,1:5]*a[:,1:5]'
                        # Make sure A is Hermitian even in the presence of rounding error
                        # xianyi/OpenBLAS#729
                        A = (A + A') / 2
                        @test rank(A) == rank(Hermitian(A))
                    end
                end

                @testset "pow" begin
                    # Integer power
                    @test (asym)^2   ≈ (Symmetric(asym)^2)::Symmetric
                    @test (asym)^-2  ≈ (Symmetric(asym)^-2)::Symmetric
                    @test (aposs)^2  ≈ (Symmetric(aposs)^2)::Symmetric
                    @test (aherm)^2  ≈ (Hermitian(aherm)^2)::Hermitian
                    @test (aherm)^-2 ≈ (Hermitian(aherm)^-2)::Hermitian
                    @test (apos)^2   ≈ (Hermitian(apos)^2)::Hermitian
                    # integer floating point power
                    @test (asym)^2.0   ≈ (Symmetric(asym)^2.0)::Symmetric
                    @test (asym)^-2.0  ≈ (Symmetric(asym)^-2.0)::Symmetric
                    @test (aposs)^2.0  ≈ (Symmetric(aposs)^2.0)::Symmetric
                    @test (aherm)^2.0  ≈ (Hermitian(aherm)^2.0)::Hermitian
                    @test (aherm)^-2.0 ≈ (Hermitian(aherm)^-2.0)::Hermitian
                    @test (apos)^2.0   ≈ (Hermitian(apos)^2.0)::Hermitian
                    # non-integer floating point power
                    @test (asym)^2.5   ≈ (Symmetric(asym)^2.5)::Symmetric
                    @test (asym)^-2.5  ≈ (Symmetric(asym)^-2.5)::Symmetric
                    @test (aposs)^2.5  ≈ (Symmetric(aposs)^2.5)::Symmetric
                    @test (aherm)^2.5  ≈ (Hermitian(aherm)^2.5)#::Hermitian
                    @test (aherm)^-2.5 ≈ (Hermitian(aherm)^-2.5)#::Hermitian
                    @test (apos)^2.5   ≈ (Hermitian(apos)^2.5)::Hermitian
                end
            end
        end

        @testset "linalg binary ops" begin
            @testset "mat * vec" begin
                @test Symmetric(asym)*x+y ≈ asym*x+y
                # testing fallbacks for transpose-vector * transpose(SymHerm)
                xadj = transpose(x)
                @test xadj * transpose(Symmetric(asym)) ≈ xadj * asym
                @test x' * Symmetric(asym) ≈ x' * asym

                @test Hermitian(aherm)*x+y ≈ aherm*x+y
                # testing fallbacks for adjoint-vector * SymHerm'
                xadj = x'
                @test x' * Hermitian(aherm) ≈ x' * aherm
                @test xadj * Hermitian(aherm)' ≈ xadj * aherm
            end

            @testset "mat * mat" begin
                C = zeros(eltya,n,n)
                @test Hermitian(aherm) * a ≈ aherm * a
                @test a * Hermitian(aherm) ≈ a * aherm
                # rectangular multiplication
                @test [a; a] * Hermitian(aherm) ≈ [a; a] * aherm
                @test Hermitian(aherm) * [a a] ≈ aherm * [a a]
                @test Hermitian(aherm) * Hermitian(aherm) ≈ aherm*aherm
                @test_throws DimensionMismatch Hermitian(aherm) * Vector{eltya}(undef, n+1)
                LinearAlgebra.mul!(C,a,Hermitian(aherm))
                @test C ≈ a*aherm

                @test Symmetric(asym) * Symmetric(asym) ≈ asym*asym
                @test Symmetric(asym) * a ≈ asym * a
                @test a * Symmetric(asym) ≈ a * asym
                # rectangular multiplication
                @test Symmetric(asym) * [a a] ≈ asym * [a a]
                @test [a; a] * Symmetric(asym) ≈ [a; a] * asym
                @test_throws DimensionMismatch Symmetric(asym) * Vector{eltya}(undef, n+1)
                LinearAlgebra.mul!(C,a,Symmetric(asym))
                @test C ≈ a*asym

                tri_b = UpperTriangular(triu(b))
                @test Array(transpose(Hermitian(aherm)) * tri_b) ≈ transpose(aherm) * Array(tri_b)
                @test Array(tri_b * transpose(Hermitian(aherm))) ≈ Array(tri_b) * transpose(aherm)
                @test Array(Hermitian(aherm)' * tri_b) ≈ aherm' * Array(tri_b)
                @test Array(tri_b * Hermitian(aherm)') ≈ Array(tri_b) * aherm'

                @test Array(transpose(Symmetric(asym)) * tri_b) ≈ transpose(asym) * Array(tri_b)
                @test Array(tri_b * transpose(Symmetric(asym))) ≈ Array(tri_b) * transpose(asym)
                @test Array(Symmetric(asym)' * tri_b) ≈ asym' * Array(tri_b)
                @test Array(tri_b * Symmetric(asym)') ≈ Array(tri_b) * asym'
            end
            @testset "solver" begin
                @test Hermitian(aherm)\x ≈ aherm\x
                @test Hermitian(aherm)\b ≈ aherm\b
                @test Symmetric(asym)\x  ≈ asym\x
                @test Symmetric(asym)\b  ≈ asym\b
                @test Hermitian(Diagonal(aherm))\x ≈ Diagonal(aherm)\x
                @test Hermitian(Matrix(Diagonal(aherm)))\b ≈ Diagonal(aherm)\b
                @test Symmetric(Diagonal(asym))\x  ≈ Diagonal(asym)\x
                @test Symmetric(Matrix(Diagonal(asym)))\b  ≈ Diagonal(asym)\b
            end
        end
        @testset "generalized dot product" begin
            for uplo in (:U, :L)
                @test dot(x, Hermitian(aherm, uplo), y) ≈ dot(x, Hermitian(aherm, uplo)*y) ≈ dot(x, Matrix(Hermitian(aherm, uplo)), y)
                @test dot(x, Hermitian(aherm, uplo), x) ≈ dot(x, Hermitian(aherm, uplo)*x) ≈ dot(x, Matrix(Hermitian(aherm, uplo)), x)
            end
            @test dot(x, Hermitian(Diagonal(a)), y) ≈ dot(x, Hermitian(Diagonal(a))*y) ≈ dot(x, Matrix(Hermitian(Diagonal(a))), y)
            @test dot(x, Hermitian(Diagonal(a)), x) ≈ dot(x, Hermitian(Diagonal(a))*x) ≈ dot(x, Matrix(Hermitian(Diagonal(a))), x)
            if eltya <: Real
                for uplo in (:U, :L)
                    @test dot(x, Symmetric(aherm, uplo), y) ≈ dot(x, Symmetric(aherm, uplo)*y) ≈ dot(x, Matrix(Symmetric(aherm, uplo)), y)
                    @test dot(x, Symmetric(aherm, uplo), x) ≈ dot(x, Symmetric(aherm, uplo)*x) ≈ dot(x, Matrix(Symmetric(aherm, uplo)), x)
                end
            end
        end

        @testset "dot product of symmetric and Hermitian matrices" begin
            for mtype in (Symmetric, Hermitian)
                symau = mtype(a, :U)
                symal = mtype(a, :L)
                msymau = Matrix(symau)
                msymal = Matrix(symal)
                @test_throws DimensionMismatch dot(symau, mtype(zeros(eltya, n-1, n-1)))
                for eltyc in (Float32, Float64, ComplexF32, ComplexF64, BigFloat, Int)
                    creal = randn(n, n)/2
                    cimag = randn(n, n)/2
                    c = eltya == Int ? rand(1:7, n, n) : convert(Matrix{eltya}, eltya <: Complex ? complex.(creal, cimag) : creal)
                    symcu = mtype(c, :U)
                    symcl = mtype(c, :L)
                    msymcu = Matrix(symcu)
                    msymcl = Matrix(symcl)
                    @test dot(symau, symcu) ≈ dot(msymau, msymcu)
                    @test dot(symau, symcl) ≈ dot(msymau, msymcl)
                    @test dot(symal, symcu) ≈ dot(msymal, msymcu)
                    @test dot(symal, symcl) ≈ dot(msymal, msymcl)
                end

                # block matrices
                blockm = [eltya == Int ? rand(1:7, 3, 3) : convert(Matrix{eltya}, eltya <: Complex ? complex.(randn(3, 3)/2, randn(3, 3)/2) : randn(3, 3)/2) for _ in 1:3, _ in 1:3]
                symblockmu = mtype(blockm, :U)
                symblockml = mtype(blockm, :L)
                msymblockmu = Matrix(symblockmu)
                msymblockml = Matrix(symblockml)
                @test dot(symblockmu, symblockmu) ≈ dot(msymblockmu, msymblockmu)
                @test dot(symblockmu, symblockml) ≈ dot(msymblockmu, msymblockml)
                @test dot(symblockml, symblockmu) ≈ dot(msymblockml, msymblockmu)
                @test dot(symblockml, symblockml) ≈ dot(msymblockml, msymblockml)
            end
        end

        @testset "kronecker product of symmetric and Hermitian matrices" begin
            for mtype in (Symmetric, Hermitian)
                symau = mtype(a, :U)
                symal = mtype(a, :L)
                msymau = Matrix(symau)
                msymal = Matrix(symal)
                for eltyc in (Float32, Float64, ComplexF32, ComplexF64, BigFloat, Int)
                    creal = randn(n, n)/2
                    cimag = randn(n, n)/2
                    c = eltya == Int ? rand(1:7, n, n) : convert(Matrix{eltya}, eltya <: Complex ? complex.(creal, cimag) : creal)
                    symcu = mtype(c, :U)
                    symcl = mtype(c, :L)
                    msymcu = Matrix(symcu)
                    msymcl = Matrix(symcl)
                    @test kron(symau, symcu) ≈ kron(msymau, msymcu)
                    @test kron(symau, symcl) ≈ kron(msymau, msymcl)
                    @test kron(symal, symcu) ≈ kron(msymal, msymcu)
                    @test kron(symal, symcl) ≈ kron(msymal, msymcl)
                end
            end
        end
    end
end

@testset "non-isbits algebra" begin
    for ST in (Symmetric, Hermitian), uplo in (:L, :U)
        M = Matrix{Complex{BigFloat}}(undef,2,2)
        M[1,1] = rand()
        M[2,2] = rand()
        M[1+(uplo==:L), 1+(uplo==:U)] = rand(ComplexF64)
        S = ST(M, uplo)
        MS = Matrix(S)
        @test real(S) == real(MS)
        @test imag(S) == imag(MS)
        @test conj(S) == conj(MS)
        @test conj!(copy(S)) == conj(MS)
        @test -S == -MS
        @test S + S == MS + MS
        @test S - S == MS - MS
        @test S*2 == 2*S == 2*MS
        @test S/2 == MS/2
        @test kron(S,S) == kron(MS,MS)
    end
    @testset "mixed uplo" begin
        Mu = Matrix{Complex{BigFloat}}(undef,2,2)
        Mu[1,1] = Mu[2,2] = 3
        Mu[1,2] = 2 + 3im
        Ml = Matrix{Complex{BigFloat}}(undef,2,2)
        Ml[1,1] = Ml[2,2] = 4
        Ml[2,1] = 4 + 5im
        for ST in (Symmetric, Hermitian)
            Su = ST(Mu, :U)
            MSu = Matrix(Su)
            Sl = ST(Ml, :L)
            MSl = Matrix(Sl)
            @test Su + Sl == Sl + Su == MSu + MSl
            @test Su - Sl == -(Sl - Su) == MSu - MSl
            @test kron(Su,Sl) == kron(MSu,MSl)
            @test kron(Sl,Su) == kron(MSl,MSu)
        end
    end
    @testset "non-strided" begin
        @testset "diagonal" begin
            for ST1 in (Symmetric, Hermitian), uplo1 in (:L, :U)
                m = ST1(Matrix{BigFloat}(undef,2,2), uplo1)
                m.data[1,1] = 1
                m.data[2,2] = 3
                m.data[1+(uplo1==:L), 1+(uplo1==:U)] = 2
                A = Array(m)
                for ST2 in (Symmetric, Hermitian), uplo2 in (:L, :U)
                    id = ST2(I(2), uplo2)
                    @test m + id == id + m == A + id
                end
            end
        end
        @testset "unit triangular" begin
            for ST1 in (Symmetric, Hermitian), uplo1 in (:L, :U)
                H1 = ST1(UnitUpperTriangular(big.(rand(Int8,4,4))), uplo1)
                M1 = Matrix(H1)
                for ST2 in (Symmetric, Hermitian), uplo2 in (:L, :U)
                    H2 = ST2(UnitUpperTriangular(big.(rand(Int8,4,4))), uplo2)
                    @test H1 + H2 == M1 + Matrix(H2)
                end
            end
        end
    end
end

@testset "Reverse operation on Symmetric" begin
    for uplo in (:U, :L)
        A = Symmetric(randn(5, 5), uplo)
        @test reverse(A, dims=1) == reverse(Matrix(A), dims=1)
        @test reverse(A, dims=2) == reverse(Matrix(A), dims=2)
        @test reverse(A)::Symmetric == reverse(Matrix(A))
    end
end

@testset "Reverse operation on Hermitian" begin
    for uplo in (:U, :L)
        A = Hermitian(randn(ComplexF64, 5, 5), uplo)
        @test reverse(A, dims=1) == reverse(Matrix(A), dims=1)
        @test reverse(A, dims=2) == reverse(Matrix(A), dims=2)
        @test reverse(A)::Hermitian == reverse(Matrix(A))
    end
end


# bug identified in PR #52318: dot products of quaternionic Hermitian matrices,
# or any number type where conj(a)*conj(b) ≠ conj(a*b):
@testset "dot Hermitian quaternion #52318" begin
    A, B = [Quaternion.(randn(3,3), randn(3, 3), randn(3, 3), randn(3,3)) |> t -> t + t' for i in 1:2]
    @test A == Hermitian(A) && B == Hermitian(B)
    @test dot(A, B) ≈ dot(Hermitian(A), Hermitian(B))
    A, B = [Quaternion.(randn(3,3), randn(3, 3), randn(3, 3), randn(3,3)) |> t -> t + transpose(t) for i in 1:2]
    @test A == Symmetric(A) && B == Symmetric(B)
    @test dot(A, B) ≈ dot(Symmetric(A), Symmetric(B))
end

# let's make sure the analogous bug will not show up with kronecker products
@testset "kron Hermitian quaternion #52318" begin
    A, B = [Quaternion.(randn(3,3), randn(3, 3), randn(3, 3), randn(3,3)) |> t -> t + t' for i in 1:2]
    @test A == Hermitian(A) && B == Hermitian(B)
    @test kron(A, B) ≈ kron(Hermitian(A), Hermitian(B))
    A, B = [Quaternion.(randn(3,3), randn(3, 3), randn(3, 3), randn(3,3)) |> t -> t + transpose(t) for i in 1:2]
    @test A == Symmetric(A) && B == Symmetric(B)
    @test kron(A, B) ≈ kron(Symmetric(A), Symmetric(B))
end

@testset "kron with symmetric/hermitian matrices of matrices" begin
    M = fill(ones(2,2), 2, 2)
    for W in (Symmetric, Hermitian)
        for (t1, t2) in ((W(M, :U), W(M, :U)), (W(M, :U), W(M, :L)), (W(M, :L), W(M, :L)))
            @test kron(t1, t2) ≈ kron(Matrix(t1), Matrix(t2))
        end
    end
end

#Issue #7647: test xsyevr, xheevr, xstevr drivers.
@testset "Eigenvalues in interval for $(typeof(Mi7647))" for Mi7647 in
        (Symmetric(diagm(0 => 1.0:3.0)),
         Hermitian(diagm(0 => 1.0:3.0)),
         Hermitian(diagm(0 => complex(1.0:3.0))),
         SymTridiagonal([1.0:3.0;], zeros(2)))
    @test eigmin(Mi7647)  == eigvals(Mi7647, 0.5, 1.5)[1] == 1.0
    @test eigmax(Mi7647)  == eigvals(Mi7647, 2.5, 3.5)[1] == 3.0
    @test eigvals(Mi7647) == eigvals(Mi7647, 0.5, 3.5) == [1.0:3.0;]
end

@testset "Hermitian wrapper ignores imaginary parts on diagonal" begin
    A = [1.0+im 2.0; 2.0 0.0]
    @test !ishermitian(A)
    @test Hermitian(A)[1,1] == 1
end

@testset "Issue #7933" begin
    A7933 = [1 2; 3 4]
    B7933 = copy(A7933)
    C7933 = Matrix(Symmetric(A7933))
    @test A7933 == B7933
end

@testset "Issues #8057 and #8058. f=$f, A=$A" for f in
        (eigen, eigvals),
            A in (Symmetric([0 1; 1 0]), Hermitian([0 im; -im 0]))
    @test_throws ArgumentError f(A, 3, 2)
    @test_throws ArgumentError f(A, 1:4)
end

@testset "Ignore imaginary part of Hermitian diagonal" begin
    A = [1.0+im 2.0; 2.0 0.0]
    @test !ishermitian(A)
    @test diag(Hermitian(A)) == real(diag(A))
end

@testset "Issue #17780" begin
    a = randn(2,2)
    a = a'a
    b = complex.(a,a)
    c = Symmetric(b)
    @test conj(c) == conj(Array(c))
    cc = copy(c)
    @test conj!(c) == conj(Array(cc))
    c = Hermitian(b + b')
    @test conj(c) == conj(Array(c))
    cc = copy(c)
    @test conj!(c) == conj(Array(cc))
end

@testset "Issue # 19225" begin
    X = [1 -1; -1 1]
    for T in (Symmetric, Hermitian)
        Y = T(copy(X))
        _Y = similar(Y)
        copyto!(_Y, Y)
        @test _Y == Y

        W = T(copy(X), :L)
        copyto!(W, Y)
        @test W.data == Y.data
        @test W.uplo != Y.uplo

        W[1,1] = 4
        @test W == T([4 -1; -1 1])
        @test_throws ArgumentError (W[1,2] = 2)
        if T == Hermitian
            @test_throws ArgumentError (W[2,2] = 3+4im)
        end

        @test Y + I == T([2 -1; -1 2])
        @test Y - I == T([0 -1; -1 0])
        @test Y * I == Y

        @test Y .+ 1 == T([2 0; 0 2])
        @test Y .- 1 == T([0 -2; -2 0])
        @test Y * 2 == T([2 -2; -2 2])
        @test Y / 1 == Y

        @test T([true false; false true]) .+ true == T([2 1; 1 2])
    end
end

@testset "Issue #21981" begin
    B = complex(rand(4,4))
    B[4,1] += 1im;
    @test ishermitian(Symmetric(B, :U))
    @test issymmetric(Hermitian(B, :U))
    B[4,1]  = real(B[4,1])
    B[1,4] += 1im
    @test ishermitian(Symmetric(B, :L))
    @test issymmetric(Hermitian(B, :L))
end

@testset "$HS solver with $RHS RHS - $T" for HS in (Hermitian, Symmetric),
        RHS in (Hermitian, Symmetric, Diagonal, UpperTriangular, LowerTriangular),
        T   in (Float64, ComplexF64)
    D = rand(T, 10, 10); D = D'D
    A = HS(D)
    B = RHS(D)
    @test A\B ≈ Matrix(A)\Matrix(B)
end

@testset "inversion of Hilbert matrix" begin
    for T in (Float64, ComplexF64)
        H = T[1/(i + j - 1) for i in 1:8, j in 1:8]
        @test norm(inv(Symmetric(H))*(H*fill(1., 8)) .- 1) ≈ 0 atol = 1e-5
        @test norm(inv(Hermitian(H))*(H*fill(1., 8)) .- 1) ≈ 0 atol = 1e-5
    end
end

@testset "eigendecomposition Algorithms" begin
    using LinearAlgebra: DivideAndConquer, QRIteration, RobustRepresentations
    for T in (Float64, ComplexF64, Float32, ComplexF32)
        n = 4
        A = T <: Real ? Symmetric(randn(T, n, n)) : Hermitian(randn(T, n, n))
        d, v = eigen(A)
        for alg in (DivideAndConquer(), QRIteration(), RobustRepresentations())
            @test (@inferred eigvals(A, alg)) ≈ d
            d2, v2 = @inferred eigen(A, alg)
            @test d2 ≈ d
            @test A * v2 ≈ v2 * Diagonal(d2)
        end
    end
end

const BASE_TEST_PATH = joinpath(Sys.BINDIR, "..", "share", "julia", "test")
isdefined(Main, :ImmutableArrays) || @eval Main include(joinpath($(BASE_TEST_PATH), "testhelpers", "ImmutableArrays.jl"))
using .Main.ImmutableArrays

@testset "Conversion to AbstractArray" begin
    # tests corresponding to #34995
    immutablemat = ImmutableArray([1 2 3; 4 5 6; 7 8 9])
    for SymType in (Symmetric, Hermitian)
        S = Float64
        symmat = SymType(immutablemat)
        @test convert(AbstractArray{S}, symmat).data isa ImmutableArray{S}
        @test convert(AbstractMatrix{S}, symmat).data isa ImmutableArray{S}
        @test AbstractArray{S}(symmat).data isa ImmutableArray{S}
        @test AbstractMatrix{S}(symmat).data isa ImmutableArray{S}
        @test convert(AbstractArray{S}, symmat) == symmat
        @test convert(AbstractMatrix{S}, symmat) == symmat
    end
end


@testset "#24572: eltype(A::HermOrSym) === eltype(parent(A))" begin
    A = rand(Float32, 3, 3)
    @test_throws TypeError Symmetric{Float64,Matrix{Float32}}(A, 'U')
    @test_throws TypeError Hermitian{Float64,Matrix{Float32}}(A, 'U')
end

@testset "fill[stored]!" begin
    for uplo in (:U, :L)
        # Hermitian
        A = Hermitian(fill(1.0+0im, 2, 2), uplo)
        @test fill!(A, 2) == fill(2, 2, 2)
        @test A.data == (uplo === :U ? [2 2; 1.0+0im 2] : [2 1.0+0im; 2 2])
        @test_throws ArgumentError fill!(A, 2+im)

        # Symmetric
        A = Symmetric(fill(1.0+im, 2, 2), uplo)
        @test fill!(A, 2) == fill(2, 2, 2)
        @test A.data == (uplo === :U ? [2 2; 1.0+im 2] : [2 1.0+im; 2 2])
    end
end

@testset "#25625 recursive transposition" begin
    A = Matrix{Matrix{Int}}(undef, 2, 2)
    A[1,1] = [1 2; 2 3]
    A[1,2] = [4 5 6; 7 8 9]
    A[2,1] = [4 7; 5 8; 6 9]
    A[2,2] = [1 2; 3 4]
    for uplo in (:U, :L)
        S = Symmetric(A, uplo)
        @test S[1,1] == A[1,1]
        @test S[1,2] == transpose(S[2,1]) == A[1,2]
        @test S[2,2] == Symmetric(A[2,2], uplo)
        @test S == transpose(S) == Matrix(S) == Matrix(transpose(S)) == transpose(Matrix(S))
    end

    B = Matrix{Matrix{Complex{Int}}}(undef, 2, 2)
    B[1,1] = [1 2+im; 2-im 3]
    B[1,2] = [4 5+1im 6-2im; 7+3im 8-4im 9+5im]
    B[2,1] = [4 7-3im; 5-1im 8+4im; 6+2im 9-5im]
    B[2,2] = [1+1im 2+2im; 3-3im 4-2im]
    for uplo in (:U, :L)
        H = Hermitian(B, uplo)
        @test H[1,1] == Hermitian(B[1,1], uplo)
        @test H[1,2] == adjoint(H[2,1]) == B[1,2]
        @test H[2,1] == adjoint(H[1,2]) == B[2,1]
        @test H[2,2] == Hermitian(B[2,2], uplo)
        @test H == adjoint(H) == Matrix(H) == Matrix(adjoint(H)) == adjoint(Matrix(H))
    end
end

@testset "getindex of diagonal element (#25972)" begin
    A = rand(ComplexF64, 2, 2)
    @test Hermitian(A, :U)[1,1] == Hermitian(A, :L)[1,1] == real(A[1,1])
end

@testset "issue #29392: SymOrHerm scaled with Number" begin
    R = rand(Float64, 2, 2); C = rand(ComplexF64, 2, 2)
    # Symmetric * Real, Real * Symmetric
    A = Symmetric(R); x = 2.0
    @test (A * x)::Symmetric == (x * A)::Symmetric
    A = Symmetric(C); x = 2.0
    @test (A * x)::Symmetric == (x * A)::Symmetric
    # Symmetric * Complex, Complex * Symmetrics
    A = Symmetric(R); x = 2.0im
    @test (A * x)::Symmetric == (x * A)::Symmetric
    A = Symmetric(C); x = 2.0im
    @test (A * x)::Symmetric == (x * A)::Symmetric
    # Hermitian * Real, Real * Hermitian
    A = Hermitian(R); x = 2.0
    @test (A * x)::Hermitian == (x * A)::Hermitian
    A = Hermitian(C); x = 2.0
    @test (A * x)::Hermitian == (x * A)::Hermitian
    # Hermitian * Complex, Complex * Hermitian
    A = Hermitian(R); x = 2.0im
    @test (A * x)::Matrix == (x * A)::Matrix
    A = Hermitian(C); x = 2.0im
    @test (A * x)::Matrix == (x * A)::Matrix
    # Symmetric / Real
    A = Symmetric(R); x = 2.0
    @test (A / x)::Symmetric == Matrix(A) / x
    A = Symmetric(C); x = 2.0
    @test (A / x)::Symmetric == Matrix(A) / x
    # Symmetric / Complex
    A = Symmetric(R); x = 2.0im
    @test (A / x)::Symmetric == Matrix(A) / x
    A = Symmetric(C); x = 2.0im
    @test (A / x)::Symmetric == Matrix(A) / x
    # Hermitian / Real
    A = Hermitian(R); x = 2.0
    @test (A / x)::Hermitian == Matrix(A) / x
    A = Hermitian(C); x = 2.0
    @test (A / x)::Hermitian == Matrix(A) / x
    # Hermitian / Complex
    A = Hermitian(R); x = 2.0im
    @test (A / x)::Matrix == Matrix(A) / x
    A = Hermitian(C); x = 2.0im
    @test (A / x)::Matrix == Matrix(A) / x
end

@testset "issue #30814: Symmetric of Hermitian if diag is not real" begin
    A = [1 2; 3 4] * (1 + im)
    B = Hermitian(A)
    @test_throws ArgumentError Symmetric(B) == Symmetric(Matrix(B))
    A[1,1] = 1; A[2,2] = 4
    @test Symmetric(B) == Symmetric(Matrix(B))
end

@testset "issue #32079: det for singular Symmetric matrix" begin
    A = ones(Float64, 3, 3)
    @test det(Symmetric(A))::Float64 == det(A) == 0.0
    @test det(Hermitian(A))::Float64 == det(A) == 0.0
    A = ones(ComplexF64, 3, 3)
    @test det(Symmetric(A))::ComplexF64 == det(A) == 0.0
    @test det(Hermitian(A))::Float64 == det(A) == 0.0
end

@testset "symmetric()/hermitian() for Numbers" begin
    @test LinearAlgebra.symmetric(1) == LinearAlgebra.symmetric(1, :U) == 1
    @test LinearAlgebra.symmetric_type(Int) == Int
    @test LinearAlgebra.hermitian(1) == LinearAlgebra.hermitian(1, :U) == 1
    @test LinearAlgebra.hermitian_type(Int) == Int
end

@testset "sqrt(nearly semidefinite)" begin
    let A = [0.9999999999999998 4.649058915617843e-16 -1.3149405273715513e-16 9.9959579317056e-17; -8.326672684688674e-16 1.0000000000000004 2.9280733590254494e-16 -2.9993900031619594e-16; 9.43689570931383e-16 -1.339206523454095e-15 1.0000000000000007 -8.550505126287743e-16; -6.245004513516506e-16 -2.0122792321330962e-16 1.183061278035052e-16 1.0000000000000002],
        B = [0.09648289218436859 0.023497875751503007 0.0 0.0; 0.023497875751503007 0.045787575150300804 0.0 0.0; 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0],
        C = Symmetric(A*B*A'), # semidefinite up to roundoff
        Csqrt = sqrt(C)
        @test Csqrt isa Symmetric{Float64}
        @test Csqrt*Csqrt ≈ C rtol=1e-14
    end
    let D = Symmetric(Matrix(Diagonal([1 0; 0 -1e-14])))
        @test sqrt(D) ≈ [1 0; 0 1e-7im] rtol=1e-14
        @test sqrt(D, rtol=1e-13) ≈ [1 0; 0 0] rtol=1e-14
        @test sqrt(D, rtol=1e-13)^2 ≈ D rtol=1e-13
    end
end

@testset "Multiplications symmetric/hermitian for $T and $S" for T in
        (Float16, Float32, Float64, BigFloat), S in (ComplexF16, ComplexF32, ComplexF64)
    let A = transpose(Symmetric(rand(S, 3, 3))), Bv = Vector(rand(T, 3)), Bm = Matrix(rand(T, 3,3))
        @test A * Bv ≈ Matrix(A) * Bv
        @test A * Bm ≈ Matrix(A) * Bm
        @test Bm * A ≈ Bm * Matrix(A)
    end
    let A = adjoint(Hermitian(rand(S, 3,3))), Bv = Vector(rand(T, 3)), Bm = Matrix(rand(T, 3,3))
        @test A * Bv ≈ Matrix(A) * Bv
        @test A * Bm ≈ Matrix(A) * Bm
        @test Bm * A ≈ Bm * Matrix(A)
    end
    let Ahrs = transpose(Hermitian(Symmetric(rand(T, 3, 3)))),
        Acs = transpose(Symmetric(rand(S, 3, 3))),
        Ahcs = transpose(Hermitian(Symmetric(rand(S, 3, 3))))

        @test Ahrs * Ahrs ≈ Ahrs * Matrix(Ahrs)
        @test Ahrs * Acs ≈ Ahrs * Matrix(Acs)
        @test Acs * Acs ≈ Matrix(Acs) * Matrix(Acs)
        @test Acs * Ahrs ≈ Matrix(Acs) * Ahrs
        @test Ahrs * Ahcs ≈ Matrix(Ahrs) * Ahcs
        @test Ahcs * Ahrs ≈ Ahcs * Matrix(Ahrs)
    end
    let Ahrs = adjoint(Hermitian(Symmetric(rand(T, 3, 3)))),
        Acs = adjoint(Symmetric(rand(S, 3, 3))),
        Ahcs = adjoint(Hermitian(Symmetric(rand(S, 3, 3))))

        @test Ahrs * Ahrs ≈ Ahrs * Matrix(Ahrs)
        @test Ahcs * Ahcs ≈ Matrix(Ahcs) * Matrix(Ahcs)
        @test Ahrs * Ahcs ≈ Ahrs * Matrix(Ahcs)
        @test Acs * Ahcs ≈ Acs * Matrix(Ahcs)
        @test Ahcs * Ahrs ≈ Matrix(Ahcs) * Ahrs
        @test Ahcs * Acs ≈ Matrix(Ahcs) * Acs
    end
end

@testset "Addition/subtraction with SymTridiagonal" begin
    TR = SymTridiagonal(randn(Float64,5), randn(Float64,4))
    TC = SymTridiagonal(randn(ComplexF64,5), randn(ComplexF64,4))
    SR = Symmetric(randn(Float64,5,5))
    SC = Symmetric(randn(ComplexF64,5,5))
    HR = Hermitian(randn(Float64,5,5))
    HC = Hermitian(randn(ComplexF64,5,5))
    for op = (+,-)
        for T = (TR, TC), S = (SR, SC)
            @test op(T, S) == op(Array(T), S)
            @test op(S, T) == op(S, Array(T))
            @test op(T, S) isa Symmetric
            @test op(S, T) isa Symmetric
        end
        for H = (HR, HC)
            for T = (TR, TC)
                @test op(T, H) == op(Array(T), H)
                @test op(H, T) == op(H, Array(T))
            end
            @test op(TR, H) isa Hermitian
            @test op(H, TR) isa Hermitian
        end
    end
end

@testset "hermitian part" begin
    for T in [Float32, Complex{Float32}, Int32, Rational{Int32},
              Complex{Int32}, Complex{Rational{Int32}}]
        f, f!, t = hermitianpart, hermitianpart!, T <: Real ? transpose : adjoint
        X = T[1 2 3; 4 5 6; 7 8 9]
        T <: Complex && (X .+= im .* X)
        Xc = copy(X)
        Y = (X + t(X)) / 2
        U = f(X)
        L = f(X, :L)
        @test U isa Hermitian
        @test L isa Hermitian
        @test U.uplo == 'U'
        @test L.uplo == 'L'
        @test U == L == Y
        if T <: AbstractFloat || real(T) <: AbstractFloat
            HU = f!(X)
            @test HU == Y
            @test triu(X) == triu(Y)
            HL = f!(Xc, :L)
            @test HL == Y
            @test tril(Xc) == tril(Y)
        end
    end
    @test_throws DimensionMismatch hermitianpart(ones(1,2))
    for T in (Float64, ComplexF64), uplo in (:U, :L)
        A = [randn(T, 2, 2) for _ in 1:2, _ in 1:2]
        Aherm = hermitianpart(A, uplo)
        @test Aherm == Aherm.data == (A + A')/2
        @test Aherm isa Hermitian
        @test Aherm.uplo == LinearAlgebra.char_uplo(uplo)
    end
end

@testset "Structured display" begin
    @testset "Diagonal" begin
        d = 10:13
        D = Diagonal(d)
        for uplo in (:L, :U), SymHerm in (Symmetric, Hermitian)
            S = SymHerm(D, uplo)
            @test sprint(Base.print_matrix, S) == sprint(Base.print_matrix, D)
        end

        d = (10:13) .+ 2im
        D = Diagonal(d)
        DR = Diagonal(complex.(real.(d)))
        for uplo in (:L, :U)
            H = Hermitian(D, uplo)
            @test sprint(Base.print_matrix, H) == sprint(Base.print_matrix, DR)

            S = Symmetric(D, uplo)
            @test sprint(Base.print_matrix, S) == sprint(Base.print_matrix, D)
        end
    end
    @testset "Bidiagonal" begin
        dv, ev = 1:4, 1:3
        ST = SymTridiagonal(dv, ev)
        D = Diagonal(dv)
        for B_uplo in (:L, :U)
            B = Bidiagonal(dv, ev, B_uplo)
            for Sym_uplo in (:L, :U), SymHerm in (Symmetric, Hermitian)
                SB = SymHerm(B, Sym_uplo)
                teststr = sprint(Base.print_matrix, Sym_uplo == B_uplo ? ST : D)
                @test sprint(Base.print_matrix, SB) == teststr
                SB = SymHerm(Transpose(B), Sym_uplo)
                teststr = sprint(Base.print_matrix, Sym_uplo == B_uplo ? D : ST)
                @test sprint(Base.print_matrix, SB) == teststr
            end
        end
    end
    @testset "Tridiagonal" begin
        superd, d, subd = 3:5, 10:13, 1:3
        for uplo in (:U, :L), SymHerm in (Symmetric, Hermitian)
            S = SymHerm(Tridiagonal(subd, d, superd), uplo)
            ST = SymTridiagonal(d, uplo == :U ? superd : subd)
            @test sprint(Base.print_matrix, S) == sprint(Base.print_matrix, ST)
        end

        superd, d, subd = collect((3:5)*im), collect(Complex{Int}, 10:13), collect((1:3)*im)
        for uplo in (:U, :L)
            S = Symmetric(Tridiagonal(subd, d, superd), uplo)
            ST = SymTridiagonal(d, uplo == :U ? superd : subd)
            @test sprint(Base.print_matrix, S) == sprint(Base.print_matrix, ST)

            H = Hermitian(Tridiagonal(subd, d, superd), uplo)
            T = Tridiagonal(uplo == :L ? subd : conj(superd), d, uplo == :U ? superd : conj(subd))
            @test sprint(Base.print_matrix, H) == sprint(Base.print_matrix, T)
        end
    end
end

@testset "symmetric/hermitian for matrices" begin
    A = [1 2; 3 4]
    @test LinearAlgebra.symmetric(A) === Symmetric(A)
    @test LinearAlgebra.symmetric(A, :L) === Symmetric(A, :L)
    @test LinearAlgebra.hermitian(A) === Hermitian(A)
    @test LinearAlgebra.hermitian(A, :L) === Hermitian(A, :L)
end

@testset "custom axes" begin
    SZA = SizedArrays.SizedArray{(2,2)}([1 2; 3 4])
    for T in (Symmetric, Hermitian)
        S = T(SZA)
        r = SizedArrays.SOneTo(2)
        @test axes(S) === (r,r)
    end
end

@testset "Matrix elements" begin
    M = [UpperTriangular([1 2; 3 4]) for i in 1:2, j in 1:2]
    for T in (Symmetric, Hermitian)
        H = T(M)
        A = Array(H)
        @test A isa Matrix
        @test A == H
        A = Array{Matrix{Int}}(H)
        @test A isa Matrix{Matrix{Int}}
        @test A == H
    end
end

@testset "conj for immutable" begin
    S = Symmetric(reshape((1:16)*im, 4, 4))
    @test conj(S) == conj(Array(S))
    H = Hermitian(reshape((1:16)*im, 4, 4))
    @test conj(H) == conj(Array(H))
end

@testset "copyto! with aliasing (#39460)" begin
    M = Matrix(reshape(1:36, 6, 6))
    @testset for T in (Symmetric, Hermitian), uploA in (:U, :L), uploB in (:U, :L)
        A = T(view(M, 1:5, 1:5), uploA)
        A2 = copy(A)
        B = T(view(M, 2:6, 2:6), uploB)
        @test copyto!(B, A) == A2

        A = view(M, 2:4, 2:4)
        B = T(view(M, 1:3, 1:3), uploB)
        B2 = copy(B)
        @test copyto!(A, B) == B2
    end
end

@testset "copyto with incompatible sizes" begin
    A = zeros(3,3); B = zeros(2,2)
    @testset "copyto with incompatible sizes" begin
        for T in (Symmetric, Hermitian)
            @test_throws BoundsError copyto!(T(B), T(A))
            @test_throws "Cannot set a non-diagonal index" copyto!(T(A), T(B))
        end
    end
end

@testset "getindex with Integers" begin
    M = reshape(1:4,2,2)
    for ST in (Symmetric, Hermitian)
        S = ST(M)
        @test_throws "invalid index" S[true, true]
        @test S[1,2] == S[Int8(1),UInt16(2)] == S[big(1), Int16(2)]
    end
end

@testset "tr for block matrices" begin
    m = [1 2; 3 4]
    for b in (m, m * (1 + im))
        M = fill(b, 3, 3)
        for ST in (Symmetric, Hermitian)
            S = ST(M)
            @test tr(S) == sum(diag(S))
        end
    end
end

@testset "setindex! returns the destination" begin
    M = rand(2,2)
    for T in (Symmetric, Hermitian)
        S = T(M)
        @test setindex!(S, 0, 2, 2) === S
    end
end

@testset "partly iniitalized matrices" begin
    a = Matrix{BigFloat}(undef, 2,2)
    a[1] = 1; a[3] = 1; a[4] = 1
    h = Hermitian(a)
    s = Symmetric(a)
    d = Diagonal([1,1])
    symT = SymTridiagonal([1 1;1 1])
    @test h+d == Array(h) + Array(d)
    @test h+symT == Array(h) + Array(symT)
    @test s+d == Array(s) + Array(d)
    @test s+symT == Array(s) + Array(symT)
    @test h-d == Array(h) - Array(d)
    @test h-symT == Array(h) - Array(symT)
    @test s-d == Array(s) - Array(d)
    @test s-symT == Array(s) - Array(symT)
    @test d+h == Array(d) + Array(h)
    @test symT+h == Array(symT) + Array(h)
    @test d+s == Array(d) + Array(s)
    @test symT+s == Array(symT) + Array(s)
    @test d-h == Array(d) - Array(h)
    @test symT-h == Array(symT) - Array(h)
    @test d-s == Array(d) - Array(s)
    @test symT-s == Array(symT) - Array(s)
end

end # module TestSymmetric
