Fix issues with in-place map/broadcast

Project.toml

@@ -1,7 +1,7 @@
 name = "SparseArraysBase"
 uuid = "0d5efcca-f356-4864-8770-e1ed8d78f208"
 authors = ["ITensor developers <[email protected]> and contributors"]
-version = "0.2.8"
+version = "0.2.9"
 
 [deps]
 Accessors = "7d9f7c33-5ae7-4f3b-8dc6-eff91059b697"

src/abstractsparsearrayinterface.jl

@@ -203,15 +203,25 @@
   return SparseArrayDOK{T}(size...)
 end
 
+# map over a specified subset of indices of the inputs.
+function map_indices! end
+
+@interface interface::AbstractArrayInterface function map_indices!(
+  f, a_dest::AbstractArray, indices, as::AbstractArray...
+)
+  for I in indices
+    a_dest[I] = f(map(a -> a[I], as)...)
+  end
+  return a_dest
+end
+
 # 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
+  @interface interface map_indices!(f, a_dest, eachstoredindex(as...), as...)
   return a_dest
 end
 
@@ -221,9 +231,7 @@
 @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
+  @interface interface map_indices!(f, a_dest, eachindex(as...), as...)
   return a_dest
 end
 
@@ -261,19 +269,18 @@
     @interface interface map_all!(f, a_dest, as...)
     return a_dest
   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...)
+  # Unalias the inputs from the destination
+  # to make sure the inputs aren't overwritten incorrectly.
+  # See: https://github.com/JuliaLang/julia/blob/v1.11.2/base/broadcast.jl#L935-L948
+  as = map(a -> a_dest === a ? a : Base.unalias(a_dest, a), as)
+  indices_stored = eachstoredindex(as...)
+  if eachstoredindex(a_dest) ⊈ indices_stored
+    # If not all indices being mapped over are stored in the destination,
+    # zero out the destination. An extreme example of this is when
+    # the sources are sparse but the destination is dense.
+    @interface interface zero!(a_dest)
+  end
+  @interface interface map_indices!(f, a_dest, indices_stored, as...)
   return a_dest
 end