diff --git a/Project.toml b/Project.toml index 10d69842f..505e078ee 100644 --- a/Project.toml +++ b/Project.toml @@ -54,7 +54,7 @@ FiniteDifferences = "0.12" GPUArrays = "11.4.1" LRUCache = "1.6" LinearAlgebra = "1" -MatrixAlgebraKit = "0.6.8" +MatrixAlgebraKit = "0.6.9" Mooncake = "0.5.27" OhMyThreads = "0.8.0" Printf = "1" diff --git a/docs/src/man/linearalgebra.md b/docs/src/man/linearalgebra.md index cd545d65a..92f895ce3 100644 --- a/docs/src/man/linearalgebra.md +++ b/docs/src/man/linearalgebra.md @@ -40,7 +40,7 @@ Note that, because the adjoint interchanges domain and codomain, we have `space( When tensor map instances are endomorphisms, i.e. they have the same domain and codomain, there is a multiplicative identity which can be obtained as `one(t)` or `one!(t)`, where the latter overwrites the contents of `t`. The multiplicative identity on a space `V` can also be obtained using `id(A, V)` as discussed [above](@ref ss_tensor_construction), such that for a general homomorphism `t′`, we have `t′ == id(codomain(t′)) * t′ == t′ * id(domain(t′))`. -Returning to the case of endomorphisms `t`, we can compute the trace via `tr(t)` and exponentiate them using `exp(t)`, or if the contents of `t` can be destroyed in the process, `exp!(t)`. +Returning to the case of endomorphisms `t`, we can compute the trace via `tr(t)` and exponentiate them using `exp(t)` (or the more general `exponential(t)`), or if the contents of `t` can be destroyed in the process, `exponential!(t)`. Furthermore, there are a number of tensor factorizations for both endomorphisms and general homomorphisms that we discuss on the [Tensor factorizations](@ref ss_tensor_factorization) page. Finally, there are a number of operations that also belong in this paragraph because of their analogy to common matrix operations. diff --git a/src/TensorKit.jl b/src/TensorKit.jl index 60b4d44b4..f20859dc6 100644 --- a/src/TensorKit.jl +++ b/src/TensorKit.jl @@ -82,7 +82,7 @@ export left_orth, right_orth, left_null, right_null, qr_full, qr_compact, qr_null, lq_full, lq_compact, lq_null, qr_full!, qr_compact!, qr_null!, lq_full!, lq_compact!, lq_null!, svd_compact!, svd_full!, svd_trunc!, svd_compact, svd_full, svd_trunc, svd_vals, svd_vals!, - exp, exp!, + exp, exp!, exponential, exponential!, eigh_full!, eigh_full, eigh_trunc!, eigh_trunc, eigh_vals!, eigh_vals, eig_full!, eig_full, eig_trunc!, eig_trunc, eig_vals!, eig_vals, eigen, eigen!, diff --git a/src/factorizations/matrixalgebrakit.jl b/src/factorizations/matrixalgebrakit.jl index 83d53fb0b..9bb8531b7 100644 --- a/src/factorizations/matrixalgebrakit.jl +++ b/src/factorizations/matrixalgebrakit.jl @@ -8,6 +8,7 @@ for f in :eig_full, :eig_vals, :eigh_full, :eigh_vals, :left_polar, :right_polar, :project_hermitian, :project_antihermitian, :project_isometric, + :exponential, ] f! = Symbol(f, :!) @eval function MAK.default_algorithm(::typeof($f!), ::Type{T}; kwargs...) where {T <: AbstractTensorMap} @@ -18,6 +19,11 @@ for f in end end +MAK.default_algorithm(::typeof(exponential!), ::Type{Tuple{E, T}}; kwargs...) where {E <: Number, T <: AbstractTensorMap} = + MAK.default_algorithm(exponential!, blocktype(T); kwargs...) +MAK.copy_input(::typeof(exponential), (τ, t)::Tuple{E, T}) where {E <: Number, T <: AbstractTensorMap} = + (τ, copy_oftype(t, (E <: Complex ? complex : identity)(factorisation_scalartype(exponential, t)))) + _select_truncation(f, ::AbstractTensorMap, trunc::TruncationStrategy) = trunc function _select_truncation(::typeof(left_null!), ::AbstractTensorMap, trunc::NamedTuple) return MAK.null_truncation_strategy(; trunc...) @@ -49,9 +55,10 @@ for f! in ( :qr_null!, :lq_null!, :svd_vals!, :eig_vals!, :eigh_vals!, :project_hermitian!, :project_antihermitian!, :project_isometric!, + :exponential!, ) @eval function MAK.$f!(t::AbstractTensorMap, N, alg::AbstractAlgorithm) - $(f! in (:eig_vals!, :eigh_vals!, :project_hermitian!, :project_antihermitian!) && :(LinearAlgebra.checksquare(t))) + $(f! in (:eig_vals!, :eigh_vals!, :project_hermitian!, :project_antihermitian!, :exponential!) && :(LinearAlgebra.checksquare(t))) foreachblock(t, N) do _, (tblock, Nblock) Nblock′ = $f!(tblock, Nblock, alg) # deal with the case where the output is not the same as the input @@ -62,6 +69,19 @@ for f! in ( end end +# Exponential with Tuple +function MAK.exponential!((τ, t)::Tuple{E, T}, N, alg::AbstractAlgorithm) where {E <: Number, T <: AbstractTensorMap} + LinearAlgebra.checksquare(t) + foreachblock(t, N) do _, (tblock, Nblock) + Nblock′ = exponential!((τ, tblock), Nblock, alg) + # deal with the case where the output is not the same as the input + Nblock === Nblock′ || copy!(Nblock, Nblock′) + return nothing + end + return N +end + + MAK.zero!(t::AbstractTensorMap) = zerovector!(t) # Default algorithm @@ -76,6 +96,7 @@ for f in [ :left_polar, :right_polar, :left_orth, :right_orth, :left_null, :right_null, :project_hermitian, :project_antihermitian, :project_isometric, + :exponential, ] f! = Symbol(f, :!) @eval MAK.$f!(t::AbstractTensorMap, alg::DefaultAlgorithm) = @@ -95,6 +116,12 @@ for f in [ MAK.$f!(t, out, MAK.select_algorithm(MAK.$f!, t, nothing; alg.kwargs...)) end +# resolve `DefaultAlgorithm` for the tuple form at the tensor level, mirroring the loop below +MAK.exponential!((τ, t)::Tuple{E, T}, alg::DefaultAlgorithm) where {E <: Number, T <: AbstractTensorMap} = + MAK.exponential!((τ, t), MAK.select_algorithm(exponential!, t, nothing; alg.kwargs...)) +MAK.exponential!((τ, t)::Tuple{E, T}, out, alg::DefaultAlgorithm) where {E <: Number, T <: AbstractTensorMap} = + MAK.exponential!((τ, t), out, MAK.select_algorithm(exponential!, t, nothing; alg.kwargs...)) + # Singular value decomposition # ---------------------------- @@ -221,3 +248,9 @@ MAK.initialize_output(::typeof(project_antihermitian!), tsrc::AbstractTensorMap, tsrc MAK.initialize_output(::typeof(project_isometric!), tsrc::AbstractTensorMap, ::AbstractAlgorithm) = similar(tsrc) + +# Exponential +# ---------------- +MAK.initialize_output(::typeof(exponential!), t::AbstractTensorMap, ::AbstractAlgorithm) = t +MAK.initialize_output(::typeof(exponential!), (τ, t)::Tuple{Number, AbstractTensorMap}, ::AbstractAlgorithm) = t +MAK.initialize_output(::typeof(exponential!), (τ, t)::Tuple{T1, AbstractTensorMap{T2}}, ::AbstractAlgorithm) where {T1 <: Complex, T2 <: Real} = similar(t, complex(eltype(t))) diff --git a/src/factorizations/utility.jl b/src/factorizations/utility.jl index 4d5e1bb00..0653cd7c6 100644 --- a/src/factorizations/utility.jl +++ b/src/factorizations/utility.jl @@ -5,7 +5,7 @@ end factorisation_scalartype(f, t) = factorisation_scalartype(t) function copy_oftype(t::AbstractTensorMap, T::Type{<:Number}) - return copy!(similar(t, T, space(t)), t) + return copy!(similar(t, T), t) end function _reverse!(t::AbstractTensorMap; dims = :) diff --git a/src/tensors/linalg.jl b/src/tensors/linalg.jl index 40a0e0024..4e5e4cce2 100644 --- a/src/tensors/linalg.jl +++ b/src/tensors/linalg.jl @@ -41,7 +41,7 @@ function compose(A::AbstractTensorMap, B::AbstractTensorMap) end Base.:*(t1::AbstractTensorMap, t2::AbstractTensorMap) = compose(t1, t2) -Base.exp(t::AbstractTensorMap) = exp!(copy(t)) +Base.exp(t::AbstractTensorMap) = exponential(t) function Base.:^(t::AbstractTensorMap, p::Integer) return p < 0 ? Base.power_by_squaring(inv(t), -p) : Base.power_by_squaring(t, p) end @@ -416,15 +416,7 @@ function Base.:(/)(t1::AbstractTensorMap, t2::AbstractTensorMap) return t end -# TensorMap exponentation: -function exp!(t::TensorMap) - domain(t) == codomain(t) || - error("Exponential of a tensor only exist when domain == codomain.") - for (c, b) in blocks(t) - copy!(b, LinearAlgebra.exp!(b)) - end - return t -end +@deprecate exp!(t) exponential!(t) # Sylvester equation with TensorMap objects: function LinearAlgebra.sylvester(A::AbstractTensorMap, B::AbstractTensorMap, C::AbstractTensorMap) diff --git a/test/tensors/exponential.jl b/test/tensors/exponential.jl new file mode 100644 index 000000000..16a6f7cca --- /dev/null +++ b/test/tensors/exponential.jl @@ -0,0 +1,91 @@ +using Test, TestExtras +using TensorKit +using MatrixAlgebraKit: DefaultAlgorithm, MatrixFunctionViaLA, MatrixFunctionViaEig, + MatrixFunctionViaEigh, MatrixFunctionViaTaylor +using Random + +spacelist = default_spacelist(fast_tests) +scalartypes = (Float32, Float64, ComplexF64) + +# algorithms that agree on Hermitian input +hermitian_algs = ( + MatrixFunctionViaLA(), MatrixFunctionViaEig(DefaultAlgorithm()), + MatrixFunctionViaEigh(DefaultAlgorithm()), MatrixFunctionViaTaylor(), +) +# algorithms valid for general (non-Hermitian) input +general_algs = ( + MatrixFunctionViaLA(), MatrixFunctionViaEig(DefaultAlgorithm()), + MatrixFunctionViaTaylor(), +) + +for V in spacelist + I = sectortype(first(V)) + Istr = TensorKit.type_repr(I) + println("---------------------------------------") + println("Matrix exponentials with symmetry: $Istr") + println("---------------------------------------") + @timedtestset "Matrix exponentials with symmetry: $Istr" verbose = true begin + V1, V2, V3, V4, V5 = V + W = V1 ⊗ V2 ⊗ V3 + Vd = fuse(V1 ⊗ V2) + + # explicit (non-diagonal) algorithms only apply to dense endomorphisms; + # `DiagonalTensorMap` inputs are exercised through the default algorithm below + @testset "exponential for Hermitian matrices" begin + for T1 in scalartypes, T2 in scalartypes, + A in (randn(T1, V1, V1), randn(T1, W, W)) + + A = project_hermitian!(A) + τ = rand(T2) + + expA = @constinferred exponential(A) + expτA = @constinferred exponential((τ, A)) + + for alg in hermitian_algs + @test expA ≈ @constinferred exponential(A, alg) + @test expτA ≈ @constinferred exponential((τ, A), alg) + end + end + end + + @testset "exponential! for general matrices" begin + for T1 in scalartypes, T2 in scalartypes, + A in ( + randn(T1, V1, V1), randn(T1, W, W), + DiagonalTensorMap(randn(T1, reduceddim(Vd)), Vd), + ) + + τ = rand(T2) + + expA = @constinferred exponential(A) + if !(A isa DiagonalTensorMap) # diagonal only supports the default algorithm == DiagonalAlgorithm + for alg in general_algs + @test expA ≈ exponential(A, alg) + end + end + + @test exponential!(copy(A)) ≈ exponential!((1.0, copy(A))) + + # exp(A)² == exp(2A) + @test expA * expA ≈ exponential((2, A)) + + # in-place semantics: aliases the input, unless a complex scalar forces + # a real tensor to widen to complex + Ain = copy(A) + A2 = @constinferred exponential!((τ, Ain)) + A isa DiagonalTensorMap && @test A2 isa DiagonalTensorMap + if T1 <: Real && T2 <: Complex + @test A2 !== Ain + else + @test A2 === Ain + end + + # exp(τA) and exp(-τA) are inverse + # the inverse roundtrip is ill-conditioned; only assert at full (Float64) precision + expτA = exponential!((τ, copy(A))) + expmτA = exponential!((-τ, copy(A))) + real(scalartype(expτA)) == Float64 && @test expτA * expmτA ≈ id(scalartype(expτA), domain(A)) + end + end + end +end