Merge #19 from branch array-interface-support

Author: goerz

Project.toml

@@ -9,7 +9,14 @@ QuantumControl = "8a270532-f23f-47a8-83a9-b33d10cad486"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 
+[weakdeps]
+ArrayInterface = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
+
+[extensions]
+QuantumGradientGeneratorsArrayInterfaceExt = "ArrayInterface"
+
 [compat]
+ArrayInterface = "7.0"
 LinearAlgebra = "1"
 QuantumControl = ">=0.11.0"
 Random = "1"

ext/QuantumGradientGeneratorsArrayInterfaceExt.jl

@@ -0,0 +1,20 @@
+module QuantumGradientGeneratorsArrayInterfaceExt
+
+import ArrayInterface
+import QuantumGradientGenerators: GradVector
+import QuantumControl.QuantumPropagators.Interfaces: supports_vector_interface
+
+# The following methods are necessary for `check_state`, because `similar`
+# can return a `GradVector`, and the results of `similar` must be a mutable
+# array.
+
+ArrayInterface.ismutable(::Type{GradVector{N,T}}) where {N,T} =
+    ArrayInterface.ismutable(T) && supports_vector_interface(T)
+
+
+# Direct access to the elements of a `GradVector` is possible, but should be
+# discouraged
+
+ArrayInterface.fast_scalar_indexing(::Type{<:GradVector}) = false
+
+end