Add OperatorStyle and GeometryStyle

src/MPSKit.jl

@@ -103,6 +103,7 @@ include("utility/multiline.jl")
 include("utility/utility.jl") # random utility functions
 include("utility/plotting.jl")
 include("utility/linearcombination.jl")
+include("utility/styles.jl")
 
 # maybe we should introduce an abstract state type
 include("states/abstractmps.jl")

src/operators/abstractmpo.jl

@@ -9,7 +9,6 @@ abstract type AbstractMPO{O} <: AbstractVector{O} end
 
 # useful union types
 const SparseMPO{O <: SparseBlockTensorMap} = AbstractMPO{O}
-Base.isfinite(O::AbstractMPO) = isfinite(typeof(O))
 
 # By default, define things in terms of parent
 Base.size(mpo::AbstractMPO, args...) = size(parent(mpo), args...)

src/operators/mpo.jl

@@ -16,7 +16,10 @@ end
 Matrix Product Operator (MPO) acting on a finite tensor product space with a linear order.
 """
 const FiniteMPO{O} = MPO{O, Vector{O}}
+Base.isfinite(O::MPO) = isfinite(typeof(O))
 Base.isfinite(::Type{<:FiniteMPO}) = true
+GeometryStyle(::Type{<:FiniteMPO}) = FiniteStyle()
+OperatorStyle(::Type{<:MPO}) = MPOStyle()
 
 function FiniteMPO(Os::AbstractVector{O}) where {O}
     for i in eachindex(Os)[1:(end - 1)]
@@ -37,6 +40,7 @@ Matrix Product Operator (MPO) acting on an infinite tensor product space with a
 """
 const InfiniteMPO{O} = MPO{O, PeriodicVector{O}}
 Base.isfinite(::Type{<:InfiniteMPO}) = false
+GeometryStyle(::Type{<:InfiniteMPO}) = InfiniteStyle()
 
 function InfiniteMPO(Os::AbstractVector{O}) where {O}
     for i in eachindex(Os)

src/operators/mpohamiltonian.jl

@@ -31,9 +31,12 @@ operators in a form that is compatible with this constructor.
 struct MPOHamiltonian{TO <: JordanMPOTensor, V <: AbstractVector{TO}} <: AbstractMPO{TO}
     W::V
 end
+Base.isfinite(mpo::MPOHamiltonian) = isfinite(typeof(mpo))
+OperatorStyle(::MPOHamiltonian) = HamiltonianStyle()
 
 const FiniteMPOHamiltonian{O <: MPOTensor} = MPOHamiltonian{O, Vector{O}}
 Base.isfinite(::Type{<:FiniteMPOHamiltonian}) = true
+GeometryStyle(::Type{<:FiniteMPOHamiltonian}) = FiniteStyle()
 
 function FiniteMPOHamiltonian(Ws::AbstractVector{O}) where {O <: MPOTensor}
     for i in eachindex(Ws)[1:(end - 1)]
@@ -45,6 +48,7 @@ end
 
 const InfiniteMPOHamiltonian{O <: MPOTensor} = MPOHamiltonian{O, PeriodicVector{O}}
 Base.isfinite(::Type{<:InfiniteMPOHamiltonian}) = false
+GeometryStyle(::Type{<:InfiniteMPOHamiltonian}) = InfiniteStyle()
 
 function InfiniteMPOHamiltonian(Ws::AbstractVector{O}) where {O <: MPOTensor}
     for i in eachindex(Ws)

src/states/abstractmps.jl

@@ -15,7 +15,7 @@ const MPSTensor{S} = GenericMPSTensor{S, 2} # the usual mps tensors on which we
 
 """
     MPSTensor([f, eltype], d::Int, left_D::Int, [right_D]::Int])
-    MPSTensor([f, eltype], physicalspace::Union{S,CompositeSpace{S}}, 
+    MPSTensor([f, eltype], physicalspace::Union{S,CompositeSpace{S}},
               left_virtualspace::S, [right_virtualspace]::S) where {S<:ElementarySpace}
 
 Construct an `MPSTensor` with given physical and virtual spaces.
@@ -173,6 +173,7 @@ abstract type AbstractFiniteMPS <: AbstractMPS end
 
 Base.eltype(ψ::AbstractMPS) = eltype(typeof(ψ))
 VectorInterface.scalartype(T::Type{<:AbstractMPS}) = scalartype(site_type(T))
+Base.isfinite(ψ::AbstractMPS) = isfinite(typeof(ψ))
 
 function Base.checkbounds(ψ::AbstractMPS, i)
     return Base.checkbounds(Bool, ψ, i) || throw(BoundsError(ψ, i))
@@ -201,7 +202,7 @@ TensorKit.sectortype(ψtype::Type{<:AbstractMPS}) = sectortype(site_type(ψtype)
 
 """
     left_virtualspace(ψ::AbstractMPS, [pos=1:length(ψ)])
-    
+
 Return the virtual space of the bond to the left of sites `pos`.
 
 !!! warning

src/states/finitemps.jl

@@ -311,7 +311,8 @@ function Base.similar(ψ::FiniteMPS{A, B}) where {A, B}
     return FiniteMPS{A, B}(similar(ψ.ALs), similar(ψ.ARs), similar(ψ.ACs), similar(ψ.Cs))
 end
 
-Base.isfinite(ψ::FiniteMPS) = true
+Base.isfinite(::Type{<:FiniteMPS}) = true
+GeometryStyle(::Type{<:FiniteMPS}) = FiniteStyle()
 
 Base.eachindex(ψ::FiniteMPS) = eachindex(ψ.AL)
 Base.eachindex(l::IndexStyle, ψ::FiniteMPS) = eachindex(l, ψ.AL)

src/states/infinitemps.jl

@@ -241,7 +241,8 @@ Base.size(ψ::InfiniteMPS, args...) = size(ψ.AL, args...)
 Base.length(ψ::InfiniteMPS) = length(ψ.AL)
 Base.eltype(ψ::InfiniteMPS) = eltype(typeof(ψ))
 Base.eltype(::Type{<:InfiniteMPS{A}}) where {A} = A
-Base.isfinite(ψ::InfiniteMPS) = false
+Base.isfinite(::Type{<:InfiniteMPS}) = false
+GeometryStyle(::Type{<:InfiniteMPS}) = InfiniteStyle()
 
 Base.copy(ψ::InfiniteMPS) = InfiniteMPS(copy(ψ.AL), copy(ψ.AR), copy(ψ.C), copy(ψ.AC))
 function Base.copy!(ψ::InfiniteMPS, ϕ::InfiniteMPS)

src/states/multilinemps.jl

@@ -101,7 +101,7 @@ Base.convert(::Type{InfiniteMPS}, st::MultilineMPS) = only(st)
 Base.eltype(t::MultilineMPS) = eltype(t[1])
 Base.copy!(ψ::MultilineMPS, ϕ::MultilineMPS) = (copy!.(parent(ψ), parent(ϕ)); ψ)
 
-Base.isfinite(ψ::MultilineMPS) = false
+Base.isfinite(::Type{<:MultilineMPS}) = false
 
 for f_space in (:physicalspace, :left_virtualspace, :right_virtualspace)
     @eval $f_space(t::MultilineMPS, i::Int, j::Int) = $f_space(t[i], j)

src/states/quasiparticle_state.jl

@@ -208,10 +208,13 @@ end
 
 # gauge independent code
 const QP{S, T1, T2} = Union{LeftGaugedQP{S, T1, T2}, RightGaugedQP{S, T1, T2}}
+# TODO: Remove FiniteQP and InfiniteQP in favor of styles.
 const FiniteQP{S <: FiniteMPS, T1, T2} = QP{S, T1, T2}
 const InfiniteQP{S <: InfiniteMPS, T1, T2} = QP{S, T1, T2}
 const MultilineQP{Q <: QP} = Multiline{Q}
 
+GeometryStyle(::Type{<:QP{S, T1, T2}}) where {S, T1, T2} = GeometryStyle(S)
+
 TensorKit.spacetype(::Union{QP{S}, Type{<:QP{S}}}) where {S} = spacetype(S)
 TensorKit.sectortype(::Union{QP{S}, Type{<:QP{S}}}) where {S} = sectortype(S)
 

src/utility/multiline.jl

@@ -54,6 +54,12 @@ function Base.repeat(A::Multiline, rows::Int, cols::Int)
     return Multiline(outer)
 end
 
+# Style
+# ----------------
+
+OperatorStyle(::Type{Multiline{T}}) where {T} = OperatorStyle(T)
+GeometryStyle(::Type{Multiline{T}}) where {T} = GeometryStyle(T)
+
 # VectorInterface
 # ---------------
 VectorInterface.scalartype(::Type{Multiline{T}}) where {T} = scalartype(T)

src/utility/styles.jl

@@ -0,0 +1,42 @@
+"""
+`OperatorStyle`
+
+Holy trait used as a dispatch tag for operator representations.
+Concrete subtypes (`MPOStyle` and `HamiltonianStyle`) indicate
+whether an operator is stored as an MPO or as a Hamiltonian.
+Use `OperatorStyle` in method signatures to select implementation-
+specific code paths for different operator types.
+
+To opt a custom operator type into this dispatch scheme implement:
+```julia
+OperatorStyle(::T) where {T<:YourOperatorType}
+```
+"""
+abstract type OperatorStyle end
+OperatorStyle(x) = OperatorStyle(typeof(x))
+OperatorStyle(T::Type) = throw(MethodError(OperatorStyle, T)) # avoid stackoverflow if not defined
+
+struct MPOStyle <: OperatorStyle end
+struct HamiltonianStyle <: OperatorStyle end
+
+
+"""
+`GeometryStyle`
+
+Holy trait used as a dispatch tag to distinguish between different
+geometry (currently finite and infinite). Concrete subtypes
+(`FiniteStyle` and `InfiniteStyle`) indicate whether a system is
+finite or infinite. Use `GeometryStyle` in method signatures to
+select implementation-specific code paths for different types.
+
+To opt a custom type into this dispatch scheme implement:
+```julia
+GeometryStyle(::T) where {T<:YourType}
+```
+"""
+abstract type GeometryStyle end
+GeometryStyle(x) = GeometryStyle(typeof(x))
+GeometryStyle(T::Type) = throw(MethodError(GeometryStyle, T)) # avoid stackoverflow if not defined
+
+struct FiniteStyle <: GeometryStyle end
+struct InfiniteStyle <: GeometryStyle end

test/operators.jl

@@ -10,6 +10,8 @@ module TestOperators
     using MPSKit
     using MPSKit: _transpose_front, _transpose_tail, C_hamiltonian, AC_hamiltonian,
         AC2_hamiltonian
+    using MPSKit: GeometryStyle, FiniteStyle, InfiniteStyle, OperatorStyle, MPOStyle,
+        HamiltonianStyle
     using TensorKit
     using TensorKit: ℙ
     using VectorInterface: One
@@ -32,6 +34,14 @@ module TestOperators
             mpo₂ = FiniteMPO(O₂)
             mpo₃ = FiniteMPO(O₃)
 
+            @test isfinite(mpo₁)
+            @test isfinite(typeof(mpo₁))
+            @test GeometryStyle(typeof(mpo₁)) == FiniteStyle()
+            @test GeometryStyle(mpo₁) == FiniteStyle()
+            @test OperatorStyle(typeof(mpo₁)) == MPOStyle()
+            @test OperatorStyle(mpo₁) == MPOStyle()
+
+
             @test @constinferred physicalspace(mpo₁) == fill(V, L)
             Vleft = @constinferred left_virtualspace(mpo₁)
             Vright = @constinferred right_virtualspace(mpo₂)
@@ -81,6 +91,22 @@ module TestOperators
         end
     end
 
+    @testset "InfiniteMPO" begin
+        P = ℂ^2
+        T = Float64
+
+        H1 = randn(T, P ← P)
+        H1 += H1'
+        H = InfiniteMPO([H1])
+
+        @test !isfinite(H)
+        @test !isfinite(typeof(H))
+        @test GeometryStyle(typeof(H)) == InfiniteStyle()
+        @test GeometryStyle(H) == InfiniteStyle()
+        @test OperatorStyle(typeof(H)) == MPOStyle()
+        @test OperatorStyle(H) == MPOStyle()
+    end
+
     @testset "MPOHamiltonian constructors" begin
         P = ℂ^2
         T = Float64
@@ -109,6 +135,13 @@ module TestOperators
         H′ = FiniteMPOHamiltonian(map(Base.Fix1(collect, Any), Ws)) # without type info
         @test H ≈ H′
 
+        @test isfinite(H)
+        @test isfinite(typeof(H))
+        @test GeometryStyle(typeof(H)) == FiniteStyle()
+        @test GeometryStyle(H) == FiniteStyle()
+        @test OperatorStyle(typeof(H)) == HamiltonianStyle()
+        @test OperatorStyle(H) == HamiltonianStyle()
+
         # Infinite
         Ws = [Wmid]
         H = InfiniteMPOHamiltonian(
@@ -119,6 +152,13 @@ module TestOperators
 
         H′ = InfiniteMPOHamiltonian(map(Base.Fix1(collect, Any), Ws)) # without type info
         @test all(parent(H) .≈ parent(H′))
+
+        @test !isfinite(H)
+        @test !isfinite(typeof(H))
+        @test GeometryStyle(typeof(H)) == InfiniteStyle()
+        @test GeometryStyle(H) == InfiniteStyle()
+        @test OperatorStyle(typeof(H)) == HamiltonianStyle()
+        @test OperatorStyle(H) == HamiltonianStyle()
     end
 
     @testset "Finite MPOHamiltonian" begin

test/states.jl

@@ -9,6 +9,7 @@ module TestStates
     using Test, TestExtras
     using MPSKit
     using MPSKit: _transpose_front, _transpose_tail
+    using MPSKit: GeometryStyle, FiniteStyle, InfiniteStyle
     using MPSKit: TransferMatrix
     using TensorKit
     using TensorKit: ℙ
@@ -25,6 +26,9 @@ module TestStates
         ψ = FiniteMPS(rand, elt, L, d, D)
 
         @test isfinite(ψ)
+        @test isfinite(typeof(ψ))
+        @test GeometryStyle(typeof(ψ)) == FiniteStyle()
+        @test GeometryStyle(ψ) == FiniteStyle()
         @test @constinferred physicalspace(ψ) == fill(d, L)
         @test all(x -> x ≾ D, @constinferred left_virtualspace(ψ))
         @test all(x -> x ≾ D, @constinferred right_virtualspace(ψ))
@@ -100,7 +104,11 @@ module TestStates
 
         ψ = InfiniteMPS([rand(elt, D * d, D), rand(elt, D * d, D)]; tol)
 
+        @test !isfinite(typeof(ψ))
         @test !isfinite(ψ)
+        @test GeometryStyle(typeof(ψ)) == InfiniteStyle()
+        @test GeometryStyle(ψ) == InfiniteStyle()
+
         @test physicalspace(ψ) == fill(d, 2)
         @test all(x -> x ≾ D, left_virtualspace(ψ))
         @test all(x -> x ≾ D, right_virtualspace(ψ))
@@ -231,6 +239,9 @@ module TestStates
             ϕ₁ = LeftGaugedQP(rand, ψ)
             ϕ₂ = LeftGaugedQP(rand, ψ)
 
+            @test GeometryStyle(ϕ₁) == FiniteStyle()
+            @test GeometryStyle(typeof(ϕ₂)) == FiniteStyle()
+
             @test @constinferred physicalspace(ϕ₁) == physicalspace(ψ)
             @test @constinferred left_virtualspace(ϕ₁) == left_virtualspace(ψ)
             @test @constinferred right_virtualspace(ϕ₁) == right_virtualspace(ψ)
@@ -266,6 +277,9 @@ module TestStates
             ϕ₁ = LeftGaugedQP(rand, ψ)
             ϕ₂ = LeftGaugedQP(rand, ψ)
 
+            @test GeometryStyle(ϕ₁) == InfiniteStyle()
+            @test GeometryStyle(typeof(ϕ₂)) == InfiniteStyle()
+
             @test @constinferred physicalspace(ϕ₁) == physicalspace(ψ)
             @test @constinferred left_virtualspace(ϕ₁) == left_virtualspace(ψ)
             @test @constinferred right_virtualspace(ϕ₁) == right_virtualspace(ψ)