Route Index and NamedUnitRange constructors through to_range

Project.toml

@@ -1,6 +1,6 @@
 name = "ITensorBase"
 uuid = "4795dd04-0d67-49bb-8f44-b89c448a1dc7"
-version = "0.8.5"
+version = "0.8.6"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
 
 [workspace]
@@ -52,7 +52,7 @@ Mooncake = "0.4.202, 0.5"
 OrderedCollections = "1.6"
 Random = "1.10"
 SimpleTraits = "0.9.4"
-TensorAlgebra = "0.11, 0.12"
+TensorAlgebra = "0.12.4"
 TensorOperations = "5.3.1"
 TermInterface = "2"
 TupleTools = "1.6"

src/index.jl

@@ -130,12 +130,13 @@ function Base.show(io::IO, i::IndexName)
 end
 
 """
-    Index(length)
-    Index(range)
+    Index(space)
 
 An index of an `ITensor`: a named unit range whose name is a freshly minted, unique
-identifier carrying tags and a prime level. `Index(2)` makes an index of length `2` over
-`Base.OneTo(2)`, and `Index(1:3)` makes one over an explicit range. Each call mints a new
+identifier carrying tags and a prime level. The argument is a space that is converted to a
+range: `Index(2)` makes an index of length `2` over `Base.OneTo(2)`,
+`Index(1:3)` makes one over an explicit range, and (with GradedArrays loaded)
+`Index([U1(0) => 2, U1(1) => 3])` makes one over a graded range. Each call mints a new
 name, so two indices built the same way are still distinct, and tensors share a dimension
 only when they share the same `Index`.
 

src/namedunitrange.jl

@@ -1,3 +1,5 @@
+using TensorAlgebra: to_range
+
 """
     NamedUnitRange{Name}
 
@@ -26,14 +28,28 @@ unnamed(i::NamedUnitRange) = i.value
 name(i::NamedUnitRange) = i.name
 unnamedtype(::Type{<:NamedUnitRange{<:Any, <:Any, Unnamed}}) where {Unnamed} = Unnamed
 
-# Construct from a range or length, minting a fresh name of the requested flavor.
-# Generic over the name type via `uniquename`, so `Index(3)` (with `Index` a
-# `NamedUnitRange{IndexName}` alias) needs no `Index`-specific constructor.
-function NamedUnitRange{Name}(r::AbstractUnitRange) where {Name}
-    return NamedUnitRange(r, uniquename(Name))
+# Construct from a space, minting a fresh name of the requested flavor. The space is
+# anything `to_range` accepts (an `Integer`, an existing range, or a sector-pair vector
+# when GradedArrays is loaded), so `Index(2)`, `Index(1:3)`, and
+# `Index([U1(0) => 2, U1(1) => 3])` all work. Generic over the name type via `uniquename`,
+# so `Index` (a `NamedUnitRange{IndexName}` alias) needs no `Index`-specific constructor.
+function NamedUnitRange{Name}(space) where {Name}
+    return NamedUnitRange{Name}(space, uniquename(Name))
+end
+# A space and an explicit name, name type fixed by the `Name` parameter: convert the space
+# to a range, then fall through to the base case below.
+function NamedUnitRange{Name}(space, name) where {Name}
+    return NamedUnitRange{Name}(to_range(space), name)
+end
+# Base case: a ready-made range and a name. Fixing `Name` here rather than inferring it
+# from `name` keeps the result a `NamedUnitRange{Name}` even if `uniquename(Name)` returns
+# a different concrete type.
+function NamedUnitRange{Name}(unnamed::AbstractUnitRange, name) where {Name}
+    return NamedUnitRange{Name, eltype(unnamed), typeof(unnamed)}(unnamed, name)
 end
-function NamedUnitRange{Name}(length::Integer) where {Name}
-    return NamedUnitRange{Name}(Base.OneTo(length))
+# A space and an explicit name, name type inferred from `name`.
+function NamedUnitRange(space, name)
+    return NamedUnitRange(to_range(space), name)
 end
 
 # This can be customized to output different named unit range types.

test/test_basics.jl

@@ -58,6 +58,14 @@ using UUIDs: UUID
         @test plev(i) == 0
         @test length(tags(i)) == 0
 
+        # An integer length is routed through `to_range` to a `Base.OneTo`, and an
+        # explicit range is passed through unchanged.
+        i = Index(3)
+        @test unnamed(i) === Base.OneTo(3)
+        i = Index(2:4)
+        @test length(i) == 3
+        @test unnamed(i) === 2:4
+
         i = settag(Index(2), "X", "Y")
         @test length(i) == 2
         @test hastag(i, "X")