Rename BlockZero to GetUnstoredBlock (ITensor#15)

Author: mtfishman

src/BlockSparseArrays.jl

@@ -2,7 +2,7 @@ module BlockSparseArrays
 include("BlockArraysExtensions/BlockArraysExtensions.jl")
 include("blocksparsearrayinterface/blocksparsearrayinterface.jl")
 include("blocksparsearrayinterface/linearalgebra.jl")
-include("blocksparsearrayinterface/blockzero.jl")
+include("blocksparsearrayinterface/getunstoredblock.jl")
 include("blocksparsearrayinterface/broadcast.jl")
 include("blocksparsearrayinterface/map.jl")
 include("blocksparsearrayinterface/arraylayouts.jl")

src/blocksparsearray/defaults.jl

@@ -38,5 +38,5 @@ function default_blocks(
   block_data::Dictionary{<:CartesianIndex{N},<:AbstractArray{<:Any,N}},
   axes::Tuple{Vararg{AbstractUnitRange,N}},
 ) where {N}
-  return SparseArrayDOK(block_data, blocklength.(axes), BlockZero(axes))
+  return SparseArrayDOK(block_data, blocklength.(axes), GetUnstoredBlock(axes))
 end

src/blocksparsearrayinterface/blocksparsearrayinterface.jl

@@ -65,7 +65,7 @@ end
 )
   # TODO: Use `Block()[]` once https://github.com/JuliaArrays/BlockArrays.jl/issues/430
   # is fixed.
-  return a[BlockIndex{0,Tuple{},Tuple{}}((), ())]
+  return a[BlockIndex()]
 end
 
 # a[1:2, 1:2]
@@ -135,7 +135,7 @@ end
 )
   # TODO: Use `Block()[]` once https://github.com/JuliaArrays/BlockArrays.jl/issues/430
   # is fixed.
-  a[BlockIndex{0,Tuple{},Tuple{}}((), ())] = value
+  a[BlockIndex()] = value
   return a
 end
 
@@ -301,6 +301,8 @@ end
 function Base.size(a::SparseSubArrayBlocks)
   return length.(axes(a))
 end
+# TODO: Define `isstored`.
+# TODO: Define `getstoredindex`, `getunstoredindex` instead.
 function Base.getindex(a::SparseSubArrayBlocks{<:Any,N}, I::Vararg{Int,N}) where {N}
   # TODO: Should this be defined as `@view a.array[Block(I)]` instead?
   return @view a.array[Block(I)]
@@ -312,9 +314,11 @@ function Base.getindex(a::SparseSubArrayBlocks{<:Any,N}, I::Vararg{Int,N}) where
   ## return @view parent_block[blockindices(parent(a.array), block, a.array.indices)...]
 end
 # TODO: This should be handled by generic `AbstractSparseArray` code.
+# TODO: Define `getstoredindex`, `getunstoredindex` instead.
 function Base.getindex(a::SparseSubArrayBlocks{<:Any,N}, I::CartesianIndex{N}) where {N}
   return a[Tuple(I)...]
 end
+# TODO: Define `setstoredindex!`, `setunstoredindex!` instead.
 function Base.setindex!(a::SparseSubArrayBlocks{<:Any,N}, value, I::Vararg{Int,N}) where {N}
   parent_blocks = @view blocks(parent(a.array))[blockrange(a)...]
   # TODO: The following line is required to instantiate
@@ -345,18 +349,11 @@ SparseArraysBase.storedlength(a::SparseSubArrayBlocks) = length(eachstoredindex(
 ##   array::Array
 ## end
 
-## TODO: Delete.
+## TODO: Define `storedvalues` instead.
 ## function SparseArraysBase.sparse_storage(a::SparseSubArrayBlocks)
 ##   return map(I -> a[I], eachstoredindex(a))
 ## end
 
-## TODO: Delete.
-## function SparseArraysBase.getindex_zero_function(a::SparseSubArrayBlocks)
-##   # TODO: Base it off of `getindex_zero_function(blocks(parent(a.array))`, but replace the
-##   # axes with `axes(a.array)`.
-##   return BlockZero(axes(a.array))
-## end
-
 function SparseArraysBase.getunstoredindex(
   a::SparseSubArrayBlocks{<:Any,N}, I::Vararg{Int,N}
 ) where {N}

src/blocksparsearrayinterface/blockzero.jl

@@ -0,0 +1,25 @@
+using ArrayLayouts: zero!
+using BlockArrays: Block
+
+struct GetUnstoredBlock{Axes}
+  axes::Axes
+end
+
+@inline function (f::GetUnstoredBlock)(
+  a::AbstractArray{<:Any,N}, I::Vararg{Int,N}
+) where {N}
+  # TODO: Make sure this works for sparse or block sparse blocks, immutable
+  # blocks, diagonal blocks, etc.!
+  b_size = ntuple(ndims(a)) do d
+    return length(f.axes[d][Block(I[d])])
+  end
+  b = similar(eltype(a), b_size)
+  zero!(b)
+  return b
+end
+# TODO: Use `Base.to_indices`.
+@inline function (f::GetUnstoredBlock)(
+  a::AbstractArray{<:Any,N}, I::CartesianIndex{N}
+) where {N}
+  return f(a, Tuple(I)...)
+end