Allow BraidingTensor to have a custom storage type (#393)

* Allow BraidingTensor to have a custom storage type

* Remove extraneous lines

Co-authored-by: Jutho <Jutho@users.noreply.github.com>

* More extraneous line removal

* A little more cleanup

* Coverage

* Update src/tensors/braidingtensor.jl

Co-authored-by: Lukas Devos <ldevos98@gmail.com>

* Use braidingtensortype

* Apply suggestions from code review

Co-authored-by: Lukas Devos <ldevos98@gmail.com>

* Update src/tensors/braidingtensor.jl

Co-authored-by: Jutho <Jutho@users.noreply.github.com>

* Update Project.toml

bump minor version

---------

Co-authored-by: Jutho <Jutho@users.noreply.github.com>
Co-authored-by: Lukas Devos <ldevos98@gmail.com>

Author: 3 people

Project.toml

@@ -1,6 +1,6 @@
 name = "TensorKit"
 uuid = "07d1fe3e-3e46-537d-9eac-e9e13d0d4cec"
-version = "0.16.4"
+version = "0.17.0"
 authors = ["Jutho Haegeman, Lukas Devos"]
 
 [deps]

ext/TensorKitAdaptExt.jl

@@ -15,8 +15,12 @@ function Adapt.adapt_structure(to, x::DiagonalTensorMap)
     data′ = adapt(to, x.data)
     return DiagonalTensorMap(data′, x.domain)
 end
-function Adapt.adapt_structure(::Type{TorA}, x::BraidingTensor) where {TorA <: Union{Number, DenseArray{<:Number}}}
-    return BraidingTensor{scalartype(TorA)}(space(x), x.adjoint)
+function Adapt.adapt_structure(::Type{T}, x::BraidingTensor{T′, S, A}) where {T <: Number, T′, S, A}
+    A′ = TensorKit.similarstoragetype(A, T)
+    return BraidingTensor{T, S, A′}(space(x), x.adjoint)
+end
+function Adapt.adapt_structure(::Type{TA}, x::BraidingTensor{T, S, A}) where {T′, TA <: DenseArray{T′}, T, S, A}
+    return BraidingTensor{T′, S, TA}(space(x), x.adjoint)
 end
 
 end

ext/TensorKitCUDAExt/TensorKitCUDAExt.jl

@@ -3,14 +3,16 @@ module TensorKitCUDAExt
 using CUDA, CUDA.CUBLAS, CUDA.CUSOLVER, LinearAlgebra
 using CUDA: @allowscalar
 using cuTENSOR: cuTENSOR
+using Strided: StridedViews
 import CUDA: rand as curand, rand! as curand!, randn as curandn, randn! as curandn!
+using CUDA.KernelAbstractions: @kernel, @index, get_backend
 
 using TensorKit
 using TensorKit.Factorizations
 using TensorKit.Strided
 using TensorKit.Factorizations: AbstractAlgorithm
 using TensorKit: SectorDict, tensormaptype, scalar, similarstoragetype, AdjointTensorMap, scalartype, project_symmetric_and_check
-import TensorKit: randisometry, rand, randn
+import TensorKit: randisometry, rand, randn, fill_braidingsubblock!
 
 using TensorKit: MatrixAlgebraKit
 
@@ -19,4 +21,18 @@ using Random
 include("cutensormap.jl")
 include("truncation.jl")
 
+function TensorKit.fill_braidingsubblock!(data::TD, val) where {T, TD <: Union{<:CuMatrix{T}, <:StridedViews.StridedView{T, 4, <:CuArray{T}}}}
+    # COV_EXCL_START
+    # kernels are not reachable by coverage
+    @kernel function fill_subblock_kernel!(subblock, val)
+        idx = @index(Global, Cartesian)
+        idx_val = idx[1] == idx[4] && idx[2] == idx[3] ? val : zero(val)
+        @inbounds subblock[idx] = idx_val
+    end
+    # COV_EXCL_STOP
+    kernel = fill_subblock_kernel!(get_backend(data))
+    kernel(data, val; ndrange = size(data))
+    return data
+end
+
 end

ext/TensorKitCUDAExt/cutensormap.jl

@@ -168,3 +168,7 @@ for f in (:sqrt, :log, :asin, :acos, :acosh, :atanh, :acoth)
         return tf
     end
 end
+
+function TensorKit._add_transform_multi!(tdst::CuTensorMap, tsrc, p, (U, structs_dst, structs_src)::Tuple{<:Array, TD, TS}, buffers, alpha, beta, backend...) where {TD, TS}
+    return TensorKit._add_transform_multi!(tdst, tsrc, p, (CUDA.Adapt.adapt(CuArray, U), structs_dst, structs_src), buffers, alpha, beta, backend...)
+end

src/planar/preprocessors.jl

@@ -83,6 +83,23 @@ _add_adjoint(ex) = Expr(TO.prime, ex)
 # spaces from the rest of the expression. Construct the explicit BraidingTensor objects and
 # insert them in the expression.
 function _construct_braidingtensors(ex)
+    function filter_f(expr)
+        if TO.istensor(expr)
+            return _remove_adjoint(TO.decomposetensor(expr)[1]) != :τ
+        elseif TO.istensorexpr(expr)
+            return any(filter_f, expr.args)
+        else
+            return false
+        end
+    end
+    function extract_tensors(tensor_ex)
+        if TO.istensor(tensor_ex)
+            return [TO.decomposetensor(tensor_ex)[1]]
+        elseif TO.istensorexpr(tensor_ex)
+            return collect(Iterators.flatmap(extract_tensors, filter(filter_f, tensor_ex.args)))
+        end
+    end
+    # get storagetype
     ex isa Expr || return ex
     if ex.head == :macrocall && ex.args[1] == Symbol("@notensor")
         return ex
@@ -104,7 +121,9 @@ function _construct_braidingtensors(ex)
                 )
             end
         end
-        newrhs, success = _construct_braidingtensors!(rhs, preargs, indexmap)
+        # if this is a definition, the lhs tensor is NOT yet defined
+        no_τ_ex = reduce(vcat, Iterators.flatmap(extract_tensors, filter(filter_f, rhs.args)); init = Symbol[])
+        newrhs, success = _construct_braidingtensors!(rhs, preargs, indexmap, no_τ_ex)
         success ||
             throw(ArgumentError("cannot determine the spaces of all braiding tensors in $ex"))
         pre = Expr(
@@ -115,7 +134,8 @@ function _construct_braidingtensors(ex)
     elseif TO.istensorexpr(ex)
         preargs = Vector{Any}()
         indexmap = Dict{Any, Any}()
-        newex, success = _construct_braidingtensors!(ex, preargs, indexmap)
+        no_τ_ex = reduce(vcat, Iterators.flatmap(extract_tensors, filter(filter_f, ex.args)); init = Symbol[])
+        newex, success = _construct_braidingtensors!(ex, preargs, indexmap, no_τ_ex)
         success ||
             throw(ArgumentError("cannot determine the spaces of all braiding tensors in $ex"))
         pre = Expr(
@@ -128,7 +148,7 @@ function _construct_braidingtensors(ex)
     end
 end
 
-function _construct_braidingtensors!(ex, preargs, indexmap) # ex is guaranteed to be a single tensor expression
+function _construct_braidingtensors!(ex, preargs, indexmap, non_braiding) # ex is guaranteed to be a single tensor expression
     if TO.isscalarexpr(ex)
         # ex could be tensorscalar call with more braiding tensors
         return _construct_braidingtensors(ex), true
@@ -163,7 +183,9 @@ function _construct_braidingtensors!(ex, preargs, indexmap) # ex is guaranteed t
             end
             if foundV1 && foundV2
                 s = gensym(:τ)
-                constructex = Expr(:call, GlobalRef(TensorKit, :BraidingTensor), V1, V2)
+                storageex = Expr(:call, GlobalRef(TensorKit, :promote_storagetype), non_braiding...)
+                braidingex = Expr(:call, GlobalRef(TensorKit, :braidingtensortype), V1, V2, storageex)
+                constructex = Expr(:call, braidingex, V1, V2)
                 push!(preargs, Expr(:(=), s, constructex))
                 obj = _is_adjoint(obj) ? _add_adjoint(s) : s
                 success = true
@@ -196,7 +218,7 @@ function _construct_braidingtensors!(ex, preargs, indexmap) # ex is guaranteed t
         newargs = Vector{Any}(undef, length(args))
         success = true
         for i in 1:length(ex.args)
-            newargs[i], successa = _construct_braidingtensors!(args[i], preargs, indexmap)
+            newargs[i], successa = _construct_braidingtensors!(args[i], preargs, indexmap, non_braiding)
             success = success && successa
         end
         newex = Expr(ex.head, newargs...)
@@ -212,7 +234,7 @@ function _construct_braidingtensors!(ex, preargs, indexmap) # ex is guaranteed t
             for i in 2:length(ex.args)
                 successes[i] && continue
                 newargs[i], successa = _construct_braidingtensors!(
-                    args[i], preargs, indexmap
+                    args[i], preargs, indexmap, non_braiding
                 )
                 successes[i] = successa
             end
@@ -232,7 +254,7 @@ function _construct_braidingtensors!(ex, preargs, indexmap) # ex is guaranteed t
         indices = [TO.getindices(arg) for arg in args]
         for i in 2:length(ex.args)
             indexmapa = copy(indexmap)
-            newargs[i], successa = _construct_braidingtensors!(args[i], preargs, indexmapa)
+            newargs[i], successa = _construct_braidingtensors!(args[i], preargs, indexmapa, non_braiding)
             for l in indices[i]
                 if !haskey(indexmap, l) && haskey(indexmapa, l)
                     indexmap[l] = indexmapa[l]
@@ -243,10 +265,10 @@ function _construct_braidingtensors!(ex, preargs, indexmap) # ex is guaranteed t
         newex = Expr(ex.head, newargs...)
         return newex, success
     elseif isexpr(ex, :call) && ex.args[1] == :/ && length(ex.args) == 3
-        newarg, success = _construct_braidingtensors!(ex.args[2], preargs, indexmap)
+        newarg, success = _construct_braidingtensors!(ex.args[2], preargs, indexmap, non_braiding)
         return Expr(:call, :/, newarg, ex.args[3]), success
     elseif isexpr(ex, :call) && ex.args[1] == :\ && length(ex.args) == 3
-        newarg, success = _construct_braidingtensors!(ex.args[3], preargs, indexmap)
+        newarg, success = _construct_braidingtensors!(ex.args[3], preargs, indexmap, non_braiding)
         return Expr(:call, :\, ex.args[2], newarg), success
     else
         error("unexpected expression $ex")

src/tensors/braidingtensor.jl

@@ -2,72 +2,78 @@
 # special (2,2) tensor that implements a standard braiding operation
 #====================================================================#
 """
-    struct BraidingTensor{T,S<:IndexSpace} <: AbstractTensorMap{T, S, 2, 2}
+    struct BraidingTensor{T, S <: IndexSpace, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 2, 2}
     BraidingTensor(V1::S, V2::S, adjoint::Bool=false) where {S<:IndexSpace}
+    BraidingTensor{T, S, A}(V1::S, V2::S, adjoint::Bool=false) where {T, S, A}
 
 Specific subtype of [`AbstractTensorMap`](@ref) for representing the braiding tensor that
 braids the first input over the second input; its inverse can be obtained as the adjoint.
 
 It holds that `domain(BraidingTensor(V1, V2)) == V1 ⊗ V2` and
-`codomain(BraidingTensor(V1, V2)) == V2 ⊗ V1`.
+`codomain(BraidingTensor(V1, V2)) == V2 ⊗ V1`. The storage type `TA`
+controls the array type of the braiding tensor used when indexing
+and multiplying with other tensors.
 """
-struct BraidingTensor{T, S} <: AbstractTensorMap{T, S, 2, 2}
+struct BraidingTensor{T, S, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 2, 2}
     V1::S
     V2::S
     adjoint::Bool
-    function BraidingTensor{T, S}(V1::S, V2::S, adjoint::Bool = false) where {T, S <: IndexSpace}
-        for a in sectors(V1)
-            for b in sectors(V2)
-                for c in (a ⊗ b)
-                    Nsymbol(a, b, c) == Nsymbol(b, a, c) ||
-                        throw(ArgumentError("Cannot define a braiding between $a and $b"))
-                end
-            end
+    function BraidingTensor{T, S, A}(V1::S, V2::S, adjoint::Bool = false) where {T, S <: IndexSpace, A <: DenseVector{T}}
+        for a in sectors(V1), b in sectors(V2), c in (a ⊗ b)
+            Nsymbol(a, b, c) == Nsymbol(b, a, c) ||
+                throw(ArgumentError("Cannot define a braiding between $a and $b"))
         end
-        return new{T, S}(V1, V2, adjoint)
+        return new{T, S, A}(V1, V2, adjoint)
         # partial construction: only construct rowr and colr when needed
     end
 end
 function BraidingTensor{T}(V1::S, V2::S, adjoint::Bool = false) where {T, S <: IndexSpace}
-    return BraidingTensor{T, S}(V1, V2, adjoint)
+    return braidingtensortype(S, T)(V1, V2, adjoint)
 end
-function BraidingTensor{T}(V1::IndexSpace, V2::IndexSpace, adjoint::Bool = false) where {T}
-    return BraidingTensor{T}(promote(V1, V2)..., adjoint)
+function BraidingTensor(V1::S, V2::S, adjoint::Bool = false) where {S <: IndexSpace}
+    T = BraidingStyle(sectortype(S)) isa SymmetricBraiding ? Float64 : ComplexF64
+    return BraidingTensor{T}(V1, V2, adjoint)
 end
 function BraidingTensor(V1::IndexSpace, V2::IndexSpace, adjoint::Bool = false)
     return BraidingTensor(promote(V1, V2)..., adjoint)
 end
-function BraidingTensor(V1::S, V2::S, adjoint::Bool = false) where {S <: IndexSpace}
-    T = BraidingStyle(sectortype(S)) isa SymmetricBraiding ? Float64 : ComplexF64
-    return BraidingTensor{T, S}(V1, V2, adjoint)
-end
 function BraidingTensor(V::HomSpace, adjoint::Bool = false)
     domain(V) == reverse(codomain(V)) ||
         throw(SpaceMismatch("Cannot define a braiding on $V"))
     return BraidingTensor(V[2], V[1], adjoint)
 end
+function BraidingTensor{T, S, A}(V::HomSpace, adjoint::Bool = false) where {T, S, A}
+    domain(V) == reverse(codomain(V)) ||
+        throw(SpaceMismatch("Cannot define a braiding on $V"))
+    return BraidingTensor{T, S, A}(V[2], V[1], adjoint)
+end
 function BraidingTensor{T}(V::HomSpace, adjoint::Bool = false) where {T}
     domain(V) == reverse(codomain(V)) ||
         throw(SpaceMismatch("Cannot define a braiding on $V"))
     return BraidingTensor{T}(V[2], V[1], adjoint)
 end
-function Base.adjoint(b::BraidingTensor{T, S}) where {T, S}
-    return BraidingTensor{T, S}(b.V1, b.V2, !b.adjoint)
-end
 
-space(b::BraidingTensor) = b.adjoint ? b.V1 ⊗ b.V2 ← b.V2 ⊗ b.V1 : b.V2 ⊗ b.V1 ← b.V1 ⊗ b.V2
+function Base.adjoint(b::BraidingTensor{T, S, A}) where {T, S, A}
+    return BraidingTensor{T, S, A}(b.V1, b.V2, !b.adjoint)
+end
 
-# specializations to ignore the storagetype of BraidingTensor
-promote_storagetype(::Type{A}, ::Type{B}) where {A <: BraidingTensor, B <: AbstractTensorMap} = storagetype(B)
-promote_storagetype(::Type{A}, ::Type{B}) where {A <: AbstractTensorMap, B <: BraidingTensor} = storagetype(A)
-promote_storagetype(::Type{A}, ::Type{B}) where {A <: BraidingTensor, B <: BraidingTensor} = storagetype(A)
+# these are here to make the preprocessing for `@planar` expressions less painful
+function braidingtensortype(::Type{S}, ::Type{TorA}) where {S <: IndexSpace, TorA}
+    A = similarstoragetype(TorA)
+    return BraidingTensor{scalartype(A), S, A}
+end
+braidingtensortype(V::S, ::Type{TorA}) where {S <: IndexSpace, TorA} = braidingtensortype(S, TorA)
+braidingtensortype(V1::S, V2::S, ::Type{TorA}) where {S <: IndexSpace, TorA} = braidingtensortype(S, TorA)
+function braidingtensortype(V1::IndexSpace, V2::IndexSpace, ::Type{TorA}) where {TorA}
+    S = promote(V1, V2)
+    return braidingtensortype(S..., TorA)
+end
+function braidingtensortype(V::HomSpace, ::Type{TorA}) where {TorA}
+    return braidingtensortype(spacetype(V), TorA)
+end
 
-promote_storagetype(::Type{T}, ::Type{A}, ::Type{B}) where {T <: Number, A <: BraidingTensor, B <: AbstractTensorMap} =
-    similarstoragetype(B, T)
-promote_storagetype(::Type{T}, ::Type{A}, ::Type{B}) where {T <: Number, A <: AbstractTensorMap, B <: BraidingTensor} =
-    similarstoragetype(A, T)
-promote_storagetype(::Type{T}, ::Type{A}, ::Type{B}) where {T <: Number, A <: BraidingTensor, B <: BraidingTensor} =
-    similarstoragetype(A, T)
+storagetype(::Type{BraidingTensor{T, S, A}}) where {T, S, A} = A
+space(b::BraidingTensor) = b.adjoint ? b.V1 ⊗ b.V2 ← b.V2 ⊗ b.V1 : b.V2 ⊗ b.V1 ← b.V1 ⊗ b.V2
 
 function Base.getindex(b::BraidingTensor)
     sectortype(b) === Trivial || throw(SectorMismatch())
@@ -99,6 +105,13 @@ function _braiding_factor(f₁, f₂, inv::Bool = false)
     return r
 end
 
+# generates scalar indexing errors on GPU
+function fill_braidingsubblock!(data, val)
+    f(I) = ((I[1] == I[4]) & (I[2] == I[3])) * val
+    return data .= f.(CartesianIndices(data))
+end
+
+
 @inline function subblock(
         b::BraidingTensor, (f₁, f₂)::Tuple{FusionTree{I, 2}, FusionTree{I, 2}}
     ) where {I <: Sector}
@@ -113,17 +126,10 @@ end
             throw(SectorMismatch())
     end
     d = (dims(codomain(b), f₁.uncoupled)..., dims(domain(b), f₂.uncoupled)...)
-    n1 = d[1] * d[2]
-    n2 = d[3] * d[4]
-    data = sreshape(StridedView(Matrix{eltype(b)}(undef, n1, n2)), d)
-    fill!(data, zero(eltype(b)))
-
+    data_parent = storagetype(b)(undef, prod(d))
+    data = sreshape(StridedView(data_parent), d)
     r = _braiding_factor(f₁, f₂, b.adjoint)
-    if !isnothing(r)
-        @inbounds for i in axes(data, 1), j in axes(data, 2)
-            data[i, j, j, i] = r
-        end
-    end
+    isnothing(r) ? zerovector!(data) : fill_braidingsubblock!(data, r)
     return data
 end
 
@@ -134,49 +140,50 @@ TensorMap(b::BraidingTensor) = copy!(similar(b), b)
 Base.convert(::Type{TensorMap}, b::BraidingTensor) = TensorMap(b)
 
 Base.complex(b::BraidingTensor{<:Complex}) = b
-function Base.complex(b::BraidingTensor)
-    return BraidingTensor{complex(scalartype(b))}(space(b), b.adjoint)
+function Base.complex(b::BraidingTensor{T, S, A}) where {T, S, A}
+    Tc = complex(T)
+    Ac = similarstoragetype(A, Tc)
+    return BraidingTensor{Tc, S, Ac}(space(b), b.adjoint)
 end
 
-function block(b::BraidingTensor, s::Sector)
-    I = sectortype(b)
-    I == typeof(s) || throw(SectorMismatch())
-
-    # TODO: probably always square?
-    m = blockdim(codomain(b), s)
-    n = blockdim(domain(b), s)
-    data = Matrix{eltype(b)}(undef, (m, n))
-
-    length(data) == 0 && return data # s ∉ blocksectors(b)
-
-    data = fill!(data, zero(eltype(b)))
-
+# Trivial
+function fill_braidingblock!(data, b::BraidingTensor, s::Trivial)
     V1, V2 = codomain(b)
-    if sectortype(b) === Trivial
-        d1, d2 = dim(V1), dim(V2)
-        subblock = sreshape(StridedView(data), (d1, d2, d2, d1))
-        @inbounds for i in axes(subblock, 1), j in axes(subblock, 2)
-            subblock[i, j, j, i] = one(eltype(b))
-        end
-        return data
-    end
+    d1, d2 = dim(V1), dim(V2)
+    subblock = sreshape(StridedView(data), (d1, d2, d2, d1))
+    fill_braidingsubblock!(subblock, one(eltype(b)))
+    return data
+end
 
+# Nontrivial
+function fill_braidingblock!(data, b::BraidingTensor, s::Sector)
     base_offset = first(blockstructure(b)[s][2]) - 1
 
     for ((f₁, f₂), (sz, str, off)) in pairs(subblockstructure(space(b)))
         (f₁.coupled == f₂.coupled == s) || continue
         r = _braiding_factor(f₁, f₂, b.adjoint)
-        isnothing(r) && continue
         # change offset to account for single block
         subblock = StridedView(data, sz, str, off - base_offset)
-        @inbounds for i in axes(subblock, 1), j in axes(subblock, 2)
-            subblock[i, j, j, i] = r
-        end
+        isnothing(r) ? zerovector!(subblock) : fill_braidingsubblock!(subblock, r)
     end
-
     return data
 end
 
+function block(b::BraidingTensor, s::Sector)
+    I = sectortype(b)
+    I == typeof(s) || throw(SectorMismatch())
+
+    # TODO: probably always square?
+    m = blockdim(codomain(b), s)
+    n = blockdim(domain(b), s)
+
+    data = reshape(storagetype(b)(undef, m * n), (m, n))
+
+    m * n == 0  && return data # s ∉ blocksectors(b)
+
+    return fill_braidingblock!(data, b, s)
+end
+
 # Index manipulations
 # -------------------
 has_shared_permute(t::BraidingTensor, ::Index2Tuple) = false