Allow BraidingTensor to have a custom storage type

Author: kshyatt

ext/TensorKitAdaptExt.jl

@@ -15,8 +15,11 @@ 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}
+    return BraidingTensor(space(x), TensorKit.similarstoragetype(A, T), x.adjoint)
+end
+function Adapt.adapt_structure(::Type{TA}, x::BraidingTensor{T, S, A}) where {TA <: DenseArray{<:Number}, T, S, A}
+    return BraidingTensor(space(x), TA, x.adjoint)
 end
 
 end

ext/TensorKitCUDAExt/TensorKitCUDAExt.jl

@@ -3,14 +3,18 @@ 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
+using CUDA.KernelAbstractions: @kernel, @index
+
 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, _set_subblock!
 
 using TensorKit: MatrixAlgebraKit
 
@@ -19,4 +23,16 @@ using Random
 include("cutensormap.jl")
 include("truncation.jl")
 
+function TensorKit._set_subblock!(data::TD, val) where {T, TD <: Union{<:CuMatrix{T}, <:StridedViews.StridedView{T, 4, <:CuArray{T}}}}
+    @kernel function fill_subblock_kernel!(subblock, val)
+        idx = @index(Global, Cartesian)
+        @inbounds subblock[idx[1], idx[2], idx[2], idx[1]] = val
+    end
+    kernel = fill_subblock_kernel!(KernelAbstractions.get_backend(data))
+    d1 = size(data, 1)
+    d2 = size(data, 2)
+    kernel(data, val; ndrange = (d1, d2))
+    return data
+end
+
 end

ext/TensorKitCUDAExt/cutensormap.jl

@@ -168,3 +168,23 @@ for f in (:sqrt, :log, :asin, :acos, :acosh, :atanh, :acoth)
         return tf
     end
 end
+
+
+function TensorKit.add_kernel_nonthreaded!(
+        ::TensorKit.FusionStyle,
+        tdst::CuTensorMap, tsrc::CuTensorMap, p, transformer::TensorKit.GenericTreeTransformer, α, β, backend...
+    )
+    # preallocate buffers
+    buffers = TensorKit.allocate_buffers(tdst, tsrc, transformer)
+
+    for subtransformer in transformer.data
+        # Special case without intermediate buffers whenever there is only a single block
+        if length(subtransformer[1]) == 1
+            TensorKit._add_transform_single!(tdst, tsrc, p, subtransformer, α, β, backend...)
+        else
+            cu_subtransformer = tuple(CUDA.adapt(CuArray, subtransformer[1]), subtransformer[2:end]...)
+            TensorKit._add_transform_multi!(tdst, tsrc, p, cu_subtransformer, buffers, α, β, backend...)
+        end
+    end
+    return nothing
+end

src/tensors/braidingtensor.jl

@@ -2,73 +2,67 @@
 # special (2,2) tensor that implements a standard braiding operation
 #====================================================================#
 """
-    struct BraidingTensor{T,S<:IndexSpace} <: AbstractTensorMap{T, S, 2, 2}
-    BraidingTensor(V1::S, V2::S, adjoint::Bool=false) where {S<:IndexSpace}
+    struct BraidingTensor{T,S<:IndexSpace,A<:DenseVector{T}} <: AbstractTensorMap{T, S, 2, 2}
+    BraidingTensor(V1::S, V2::S, ::Type{A}, adjoint::Bool=false) where {S<:IndexSpace, A <: DenseVector{<:Number}}
 
 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} <: 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 BraidingTensor{T, S, Vector{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, S, Vector{T}}(V1, V2, adjoint)
+end
+# necessary due to HomSpace ctor below
+function BraidingTensor(V1::S, V2::S, A, adjoint::Bool = false) where {S <: IndexSpace}
+    T = eltype(A)
+    return BraidingTensor{T, S, A}(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(V::HomSpace, A, adjoint::Bool = false)
+    domain(V) == reverse(codomain(V)) ||
+        throw(SpaceMismatch("Cannot define a braiding on $V"))
+    return BraidingTensor(V[2], V[1], A, 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)
+function Base.adjoint(b::BraidingTensor{T, S, A}) where {T, S, A}
+    return BraidingTensor{T, S, A}(b.V1, b.V2, !b.adjoint)
 end
 
+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
 
-# 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)
-
-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)
-
 function Base.getindex(b::BraidingTensor)
     sectortype(b) === Trivial || throw(SectorMismatch())
     (V1, V2) = domain(b)
@@ -99,6 +93,12 @@ function _braiding_factor(f₁, f₂, inv::Bool = false)
     return r
 end
 
+function _set_subblock!(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}
@@ -115,15 +115,12 @@ 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)
+    data_parent = storagetype(b)(undef, prod(d))
+    data = sreshape(StridedView(data_parent), d)
     fill!(data, zero(eltype(b)))
 
     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) && _set_subblock!(data, r)
     return data
 end
 
@@ -134,33 +131,20 @@ 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}
+    Ac = similarstoragetype(A, complex(T))
+    return BraidingTensor(space(b), Ac, 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)))
-
+function _trivial_subblock!(data, b::BraidingTensor)
     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))
+    _set_subblock!(subblock, one(eltype(b)))
+    return data
+end
 
+function _nontrivial_subblock!(data, b::BraidingTensor, s::Sector)
     base_offset = first(blockstructure(b)[s][2]) - 1
 
     for ((f₁, f₂), (sz, str, off)) in pairs(subblockstructure(space(b)))
@@ -169,14 +153,31 @@ function block(b::BraidingTensor, s::Sector)
         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
+        _set_subblock!(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)
+    fill!(data, zero(eltype(b)))
+
+    if sectortype(b) === Trivial
+        return _trivial_subblock!(data, b)
+    else
+        return _nontrivial_subblock!(data, b, s)
+    end
+end
+
 # Index manipulations
 # -------------------
 has_shared_permute(t::BraidingTensor, ::Index2Tuple) = false