More general block types in broadcast style (#145)

Author: mtfishman

Project.toml

@@ -1,7 +1,7 @@
 name = "BlockSparseArrays"
 uuid = "2c9a651f-6452-4ace-a6ac-809f4280fbb4"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.7.10"
+version = "0.7.11"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

src/abstractblocksparsearray/broadcast.jl

@@ -1,8 +1,8 @@
 using BlockArrays: AbstractBlockedUnitRange, BlockSlice
-using Base.Broadcast: Broadcast
+using Base.Broadcast: Broadcast, BroadcastStyle
 
 function Broadcast.BroadcastStyle(arraytype::Type{<:AnyAbstractBlockSparseArray})
-  return BlockSparseArrayStyle{ndims(arraytype)}()
+  return BlockSparseArrayStyle(BroadcastStyle(blocktype(arraytype)))
 end
 
 # Fix ambiguity error with `BlockArrays`.

src/blocksparsearray/blocksparsearray.jl

@@ -171,11 +171,24 @@ function BlockSparseArray{T,N,A}(
   return BlockSparseArray{T,N,A}(undef, (dim1, dim_rest...))
 end
 
+function similartype_unchecked(
+  A::Type{<:AbstractArray{T}}, axt::Type{<:Tuple{Vararg{Any,N}}}
+) where {T,N}
+  A′ = Base.promote_op(similar, A, axt)
+  return !isconcretetype(A′) ? Array{T,N} : A′
+end
+
 function BlockSparseArray{T,N}(
   ::UndefInitializer, axes::Tuple{Vararg{AbstractUnitRange{<:Integer},N}}
 ) where {T,N}
   axt = Tuple{blockaxistype.(axes)...}
-  A = similartype(Array{T}, axt)
+  # Ideally we would use:
+  # ```julia
+  # A = similartype(Array{T}, axt)
+  # ```
+  # but that doesn't work when `similar` isn't defined or
+  # isn't type stable.
+  A = similartype_unchecked(Array{T}, axt)
   return BlockSparseArray{T,N,A}(undef, axes)
 end
 

src/blocksparsearrayinterface/broadcast.jl

@@ -1,23 +1,44 @@
-using Base.Broadcast: BroadcastStyle, AbstractArrayStyle, DefaultArrayStyle, Broadcasted
+using Base.Broadcast:
+  Broadcast, BroadcastStyle, AbstractArrayStyle, DefaultArrayStyle, Broadcasted
 using GPUArraysCore: @allowscalar
 using MapBroadcast: Mapped
 using DerivableInterfaces: DerivableInterfaces, @interface
 
-abstract type AbstractBlockSparseArrayStyle{N} <: AbstractArrayStyle{N} end
+abstract type AbstractBlockSparseArrayStyle{N,B<:AbstractArrayStyle{N}} <:
+              AbstractArrayStyle{N} end
 
-function DerivableInterfaces.interface(::Type{<:AbstractBlockSparseArrayStyle})
-  return BlockSparseArrayInterface()
+blockstyle(::AbstractBlockSparseArrayStyle{N,B}) where {N,B<:AbstractArrayStyle{N}} = B()
+
+function Broadcast.BroadcastStyle(
+  style1::AbstractBlockSparseArrayStyle, style2::AbstractBlockSparseArrayStyle
+)
+  style = Broadcast.result_style(blockstyle(style1), blockstyle(style2))
+  return BlockSparseArrayStyle(style)
 end
 
-struct BlockSparseArrayStyle{N} <: AbstractBlockSparseArrayStyle{N} end
+function DerivableInterfaces.interface(
+  ::Type{<:AbstractBlockSparseArrayStyle{N,B}}
+) where {N,B<:AbstractArrayStyle{N}}
+  return BlockSparseArrayInterface(interface(B))
+end
 
-# Define for new sparse array types.
-# function Broadcast.BroadcastStyle(arraytype::Type{<:MyBlockSparseArray})
-#   return BlockSparseArrayStyle{ndims(arraytype)}()
-# end
+struct BlockSparseArrayStyle{N,B<:AbstractArrayStyle{N}} <:
+       AbstractBlockSparseArrayStyle{N,B}
+  blockstyle::B
+end
+function BlockSparseArrayStyle{N}(blockstyle::AbstractArrayStyle{N}) where {N}
+  return BlockSparseArrayStyle{N,typeof(blockstyle)}(blockstyle)
+end
 
+function BlockSparseArrayStyle{N,B}() where {N,B<:AbstractArrayStyle{N}}
+  return BlockSparseArrayStyle{N,B}(B())
+end
+BlockSparseArrayStyle{N}() where {N} = BlockSparseArrayStyle{N}(DefaultArrayStyle{N}())
 BlockSparseArrayStyle(::Val{N}) where {N} = BlockSparseArrayStyle{N}()
 BlockSparseArrayStyle{M}(::Val{N}) where {M,N} = BlockSparseArrayStyle{N}()
+function BlockSparseArrayStyle{M,B}(::Val{N}) where {M,B<:AbstractArrayStyle{M},N}
+  return BlockSparseArrayStyle{N}(B(Val(N)))
+end
 
 Broadcast.BroadcastStyle(a::BlockSparseArrayStyle, ::DefaultArrayStyle{0}) = a
 function Broadcast.BroadcastStyle(

test/test_basics.jl

@@ -33,6 +33,7 @@ using BlockSparseArrays:
   eachblockstoredindex,
   eachstoredblock,
   eachstoredblockdiagindex,
+  similartype_unchecked,
   sparsemortar,
   view!
 using GPUArraysCore: @allowscalar
@@ -44,6 +45,28 @@ using TestExtras: @constinferred
 using TypeParameterAccessors: TypeParameterAccessors, Position
 include("TestBlockSparseArraysUtils.jl")
 
+@testset "similartype_unchecked" begin
+  @test @constinferred(similartype_unchecked(Array{Float32}, NTuple{2,Int})) ===
+    Matrix{Float32}
+  @test @constinferred(similartype_unchecked(Array{Float32}, NTuple{2,Base.OneTo{Int}})) ===
+    Matrix{Float32}
+  if VERSION < v"1.11-"
+    # Not type stable in Julia 1.10.
+    @test similartype_unchecked(AbstractArray{Float32}, NTuple{2,Int}) === Matrix{Float32}
+    @test similartype_unchecked(JLArray{Float32}, NTuple{2,Int}) === JLMatrix{Float32}
+    @test similartype_unchecked(JLArray{Float32}, NTuple{2,Base.OneTo{Int}}) ===
+      JLMatrix{Float32}
+  else
+    @test @constinferred(similartype_unchecked(AbstractArray{Float32}, NTuple{2,Int})) ===
+      Matrix{Float32}
+    @test @constinferred(similartype_unchecked(JLArray{Float32}, NTuple{2,Int})) ===
+      JLMatrix{Float32}
+    @test @constinferred(
+      similartype_unchecked(JLArray{Float32}, NTuple{2,Base.OneTo{Int}})
+    ) === JLMatrix{Float32}
+  end
+end
+
 arrayts = (Array, JLArray)
 @testset "BlockSparseArrays (arraytype=$arrayt, eltype=$elt)" for arrayt in arrayts,
   elt in (Float32, Float64, Complex{Float32}, Complex{Float64})