Add support for linear indexing (#10)

Project.toml

@@ -1,7 +1,7 @@
 name = "SparseArraysBase"
 uuid = "0d5efcca-f356-4864-8770-e1ed8d78f208"
 authors = ["ITensor developers <[email protected]> and contributors"]
-version = "0.2.0"
+version = "0.2.1"
 
 [deps]
 ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
@@ -14,7 +14,7 @@ LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Aqua = "0.8.9"
 ArrayLayouts = "1.11.0"
 BroadcastMapConversion = "0.1.0"
-Derive = "0.3.0"
+Derive = "0.3.6"
 Dictionaries = "0.4.3"
 LinearAlgebra = "1.10"
 SafeTestsets = "0.1"

src/abstractsparsearrayinterface.jl

@@ -104,6 +104,27 @@ end
 # type instead so fallback functions can use abstract types.
 abstract type AbstractSparseArrayInterface <: AbstractArrayInterface end
 
+function Derive.combine_interface_rule(
+  interface1::AbstractSparseArrayInterface, interface2::AbstractSparseArrayInterface
+)
+  return error("Rule not defined.")
+end
+function Derive.combine_interface_rule(
+  interface1::Interface, interface2::Interface
+) where {Interface<:AbstractSparseArrayInterface}
+  return interface1
+end
+function Derive.combine_interface_rule(
+  interface1::AbstractSparseArrayInterface, interface2::AbstractArrayInterface
+)
+  return interface1
+end
+function Derive.combine_interface_rule(
+  interface1::AbstractArrayInterface, interface2::AbstractSparseArrayInterface
+)
+  return interface2
+end
+
 to_vec(x) = vec(collect(x))
 to_vec(x::AbstractArray) = vec(x)
 
@@ -178,7 +199,46 @@ end
   return SparseArrayDOK{T}(size...)
 end
 
-@interface ::AbstractSparseArrayInterface function Base.map!(
+# Only map the stored values of the inputs.
+function map_stored! end
+
+@interface interface::AbstractArrayInterface function map_stored!(
+  f, a_dest::AbstractArray, as::AbstractArray...
+)
+  for I in eachstoredindex(as...)
+    a_dest[I] = f(map(a -> a[I], as)...)
+  end
+  return a_dest
+end
+
+# Only map all values, not just the stored ones.
+function map_all! end
+
+@interface interface::AbstractArrayInterface function map_all!(
+  f, a_dest::AbstractArray, as::AbstractArray...
+)
+  for I in eachindex(as...)
+    a_dest[I] = map(f, map(a -> a[I], as)...)
+  end
+  return a_dest
+end
+
+using ArrayLayouts: ArrayLayouts, zero!
+
+# `zero!` isn't defined in `Base`, but it is defined in `ArrayLayouts`
+# and is useful for sparse array logic, since it can be used to empty
+# the sparse array storage.
+# We use a single function definition to minimize method ambiguities.
+@interface interface::AbstractSparseArrayInterface function ArrayLayouts.zero!(
+  a::AbstractArray
+)
+  # More generally, this codepath could be taking if `zero(eltype(a))`
+  # is defined and the elements are immutable.
+  f = eltype(a) <: Number ? Returns(zero(eltype(a))) : zero!
+  return @interface interface map_stored!(f, a, a)
+end
+
+@interface interface::AbstractSparseArrayInterface function Base.map!(
   f, a_dest::AbstractArray, as::AbstractArray...
 )
   # TODO: Define a function `preserves_unstored(a_dest, f, as...)`
@@ -194,15 +254,22 @@ end
   preserves_unstored = iszero(f(map(a -> getunstoredindex(a, I), as)...))
   if !preserves_unstored
     # Doesn't preserve unstored values, loop over all elements.
-    for I in eachindex(as...)
-      a_dest[I] = map(f, map(a -> a[I], as)...)
-    end
+    @interface interface map_all!(f, a_dest, as...)
     return a_dest
   end
-  # Define `eachstoredindex` promotion.
-  for I in eachstoredindex(as...)
-    a_dest[I] = f(map(a -> a[I], as)...)
-  end
+  # First zero out the destination.
+  # TODO: Make this more nuanced, skip when possible, for
+  # example if the sparsity of the destination is a subset of
+  # the sparsity of the sources, i.e.:
+  # ```julia
+  # if eachstoredindex(as...) ∉ eachstoredindex(a_dest)
+  #   zero!(a_dest)
+  # end
+  # ```
+  # This is the safest thing to do in general, for example
+  # if the destination is dense but the sources are sparse.
+  @interface interface zero!(a_dest)
+  @interface interface map_stored!(f, a_dest, as...)
   return a_dest
 end
 

src/sparsearrayinterface.jl

@@ -2,6 +2,21 @@ using Derive: Derive
 
 struct SparseArrayInterface <: AbstractSparseArrayInterface end
 
+# Fix ambiguity error.
+function Derive.combine_interface_rule(::SparseArrayInterface, ::SparseArrayInterface)
+  return SparseArrayInterface()
+end
+function Derive.combine_interface_rule(
+  interface1::SparseArrayInterface, interface2::AbstractSparseArrayInterface
+)
+  return interface1
+end
+function Derive.combine_interface_rule(
+  interface1::AbstractSparseArrayInterface, interface2::SparseArrayInterface
+)
+  return interface2
+end
+
 # Convenient shorthand to refer to the sparse interface.
 # Can turn a function into a sparse function with the syntax `sparse(f)`,
 # i.e. `sparse(map)(x -> 2x, randn(2, 2))` while use the sparse

src/wrappers.jl

@@ -2,14 +2,28 @@ parentvalue_to_value(a::AbstractArray, value) = value
 value_to_parentvalue(a::AbstractArray, value) = value
 eachstoredparentindex(a::AbstractArray) = eachstoredindex(parent(a))
 storedparentvalues(a::AbstractArray) = storedvalues(parent(a))
-parentindex_to_index(a::AbstractArray, I::CartesianIndex) = error()
-function parentindex_to_index(a::AbstractArray, I::Int...)
+
+function parentindex_to_index(a::AbstractArray{<:Any,N}, I::CartesianIndex{N}) where {N}
+  return throw(MethodError(parentindex_to_index, Tuple{typeof(a),typeof(I)}))
+end
+function parentindex_to_index(a::AbstractArray{<:Any,N}, I::Vararg{Int,N}) where {N}
   return Tuple(parentindex_to_index(a, CartesianIndex(I)))
 end
-index_to_parentindex(a::AbstractArray, I::CartesianIndex) = error()
-function index_to_parentindex(a::AbstractArray, I::Int...)
+# Handle linear indexing.
+function parentindex_to_index(a::AbstractArray, I::Int)
+  return parentindex_to_index(a, CartesianIndices(parent(a))[I])
+end
+
+function index_to_parentindex(a::AbstractArray{<:Any,N}, I::CartesianIndex{N}) where {N}
+  return throw(MethodError(index_to_parentindex, Tuple{typeof(a),typeof(I)}))
+end
+function index_to_parentindex(a::AbstractArray{<:Any,N}, I::Vararg{Int,N}) where {N}
   return Tuple(index_to_parentindex(a, CartesianIndex(I)))
 end
+# Handle linear indexing.
+function index_to_parentindex(a::AbstractArray, I::Int)
+  return index_to_parentindex(a, CartesianIndices(a)[I])
+end
 
 function cartesianindex_reverse(I::CartesianIndex)
   return CartesianIndex(reverse(Tuple(I)))
@@ -21,10 +35,10 @@ tuple_oneto(n) = ntuple(identity, n)
 genperm(v, perm) = map(j -> v[j], perm)
 
 using LinearAlgebra: Adjoint
-function parentindex_to_index(a::Adjoint, I::CartesianIndex)
+function parentindex_to_index(a::Adjoint, I::CartesianIndex{2})
   return cartesianindex_reverse(I)
 end
-function index_to_parentindex(a::Adjoint, I::CartesianIndex)
+function index_to_parentindex(a::Adjoint, I::CartesianIndex{2})
   return cartesianindex_reverse(I)
 end
 function parentvalue_to_value(a::Adjoint, value)
@@ -36,18 +50,18 @@ end
 
 perm(::PermutedDimsArray{<:Any,<:Any,p}) where {p} = p
 iperm(::PermutedDimsArray{<:Any,<:Any,<:Any,ip}) where {ip} = ip
-function index_to_parentindex(a::PermutedDimsArray, I::CartesianIndex)
+function index_to_parentindex(a::PermutedDimsArray{<:Any,N}, I::CartesianIndex{N}) where {N}
   return CartesianIndex(genperm(I, iperm(a)))
 end
-function parentindex_to_index(a::PermutedDimsArray, I::CartesianIndex)
+function parentindex_to_index(a::PermutedDimsArray{<:Any,N}, I::CartesianIndex{N}) where {N}
   return CartesianIndex(genperm(I, perm(a)))
 end
 
 using Base: ReshapedArray
-function parentindex_to_index(a::ReshapedArray, I::CartesianIndex)
+function parentindex_to_index(a::ReshapedArray{<:Any,N}, I::CartesianIndex{N}) where {N}
   return CartesianIndices(size(a))[LinearIndices(parent(a))[I]]
 end
-function index_to_parentindex(a::ReshapedArray, I::CartesianIndex)
+function index_to_parentindex(a::ReshapedArray{<:Any,N}, I::CartesianIndex{N}) where {N}
   return CartesianIndices(parent(a))[LinearIndices(size(a))[I]]
 end
 
@@ -56,9 +70,15 @@ function eachstoredparentindex(a::SubArray)
     return all(d -> I[d] ∈ parentindices(a)[d], 1:ndims(parent(a)))
   end
 end
+# Don't constrain the number of dimensions of the array
+# and index since the parent array can have a different
+# number of dimensions than the `SubArray`.
 function index_to_parentindex(a::SubArray, I::CartesianIndex)
   return CartesianIndex(Base.reindex(parentindices(a), Tuple(I)))
 end
+# Don't constrain the number of dimensions of the array
+# and index since the parent array can have a different
+# number of dimensions than the `SubArray`.
 function parentindex_to_index(a::SubArray, I::CartesianIndex)
   nonscalardims = filter(tuple_oneto(ndims(parent(a)))) do d
     return !(parentindices(a)[d] isa Real)
@@ -81,10 +101,10 @@ function storedparentvalues(a::SubArray)
 end
 
 using LinearAlgebra: Transpose
-function parentindex_to_index(a::Transpose, I::CartesianIndex)
+function parentindex_to_index(a::Transpose, I::CartesianIndex{2})
   return cartesianindex_reverse(I)
 end
-function index_to_parentindex(a::Transpose, I::CartesianIndex)
+function index_to_parentindex(a::Transpose, I::CartesianIndex{2})
   return cartesianindex_reverse(I)
 end
 function parentvalue_to_value(a::Transpose, value)