ITensor · mtfishman · Sep 9, 2026 · Aug 29, 2026 · Aug 31, 2026 · Sep 9, 2026
diff --git a/Project.toml b/Project.toml
@@ -41,7 +41,7 @@ ITensorNetworksTensorOperationsExt = "TensorOperations"
 [compat]
 Accessors = "0.1.42"
 Adapt = "4"
-DataGraphs = "0.4.1, 0.5"
+DataGraphs = "0.6"
 Dictionaries = "0.4"
 DocStringExtensions = "0.9"
 Graphs = "1.8"
@@ -51,7 +51,7 @@ IsApprox = "0.1, 1, 2"
 KrylovKit = "0.6, 0.7, 0.8, 0.9, 0.10"
 MacroTools = "0.5"
 NDTensors = "0.3, 0.4"
-NamedGraphs = "0.11.1, 0.12, 0.13"
+NamedGraphs = "0.14"
 OMEinsumContractionOrders = "0.8.3, 0.9, 1"
 SimpleTraits = "0.9"
 SplitApplyCombine = "1.2"

diff --git a/docs/Project.toml b/docs/Project.toml
@@ -19,6 +19,6 @@ ITensorFormatter = "0.2.27"
 ITensorNetworks = "0.23"
 ITensors = "0.9"
 Literate = "2.20.1"
-NamedGraphs = "0.11, 0.12, 0.13"
+NamedGraphs = "0.14"
 OMEinsumContractionOrders = "1.2.2"
 TensorOperations = "5.5"
diff --git a/docs/make.jl b/docs/make.jl
@@ -49,6 +49,7 @@ makedocs(;
             "Deprecated Methods" => "deprecated_methods.md",
         ],
         "API Reference" => "reference.md",
+        "Changelog" => "changelog.md",
     ]
 )
 

diff --git a/docs/src/changelog.md b/docs/src/changelog.md
@@ -0,0 +1,15 @@
+# Changelog
+
+## [0.23.0](https://github.com/ITensor/ITensorNetworks.jl/compare/v0.22.0...main) - Unreleased
+
+### Breaking changes
+
+- Requires NamedGraphs v0.14. The network types here are `AbstractNamedGraph`
+  subtypes, so its breaking changes carry through to them, including the output
+  types of `vertices` and `edges` and the return values of the mutating
+  functions. See the
+  [NamedGraphs changelog](https://itensor.github.io/NamedGraphs.jl/stable/changelog/)
+  ([#384](https://github.com/ITensor/ITensorNetworks.jl/pull/384)).
+- The leaf type of a contraction sequence is `ITensorNetworks.Key`, where it was
+  `NamedGraphs.Keys.Key`
+  ([#384](https://github.com/ITensor/ITensorNetworks.jl/pull/384)).
diff --git a/docs/src/computing_properties.md b/docs/src/computing_properties.md
@@ -6,8 +6,7 @@ using ITensorNetworks:
     ITensorNetwork, TreeTensorNetwork, expect, inner, loginner, normalize, siteinds
 using ITensors: Index, random_itensor
 using LinearAlgebra: norm
-using NamedGraphs.GraphsExtensions: incident_edges
-using NamedGraphs.NamedGraphGenerators: named_grid
+using NamedGraphs: incident_edges, named_grid
 
 function random_state(g, s; link_space)
     l = Dict(e => Index(link_space, "Link") for e in edges(g))

diff --git a/docs/src/developer_methods.md b/docs/src/developer_methods.md
@@ -168,7 +168,7 @@
 * Tree-traversal sequence: cover `g` with a forest, then for each tree push a post-order
   DFS sweep followed by its reverse — gives a back-and-forth sequence covering every edge (`edge_sequences.jl`):
   ```julia
-  edge_sequence(::Algorithm"forest_cover", g; root_vertex = GraphsExtensions.default_root_vertex)
+  edge_sequence(::Algorithm"forest_cover", g; root_vertex = default_root_vertex)
   ```
 
 * Parallel sequence: each edge (and its reverse) as its own one-edge group, suitable

diff --git a/docs/src/experimental_methods.md b/docs/src/experimental_methods.md
@@ -55,13 +55,13 @@ Methods which still need to be discussed, modified, or deprecated.
 * Sweep-based truncation. The whole-TTN form orthogonalizes towards `src(e)` before
   each bond truncation; the edge form lifts `truncate` from the underlying `ITensorNetwork` (`treetensornetworks/abstracttreetensornetwork.jl`):
   ```julia
-  truncate(tn::AbstractTTN; root_vertex = GraphsExtensions.default_root_vertex(tn), kwargs...)
+  truncate(tn::AbstractTTN; root_vertex = default_root_vertex(tn), kwargs...)
   truncate(tn::AbstractTTN, edge::AbstractEdge; kwargs...)
   ```
 
 * Contract the whole tree into a single `ITensor` via a reverse post-order DFS sequence (`treetensornetworks/abstracttreetensornetwork.jl`):
   ```julia
-  contract(tn::AbstractTTN, root_vertex = GraphsExtensions.default_root_vertex(tn); kwargs...)
+  contract(tn::AbstractTTN, root_vertex = default_root_vertex(tn); kwargs...)
   ```
 
 * Inner product `⟨x|y⟩`, matrix element `⟨y|A|x⟩`, and four-network form `⟨B|y|A|x⟩`,

diff --git a/docs/src/itensor_networks.md b/docs/src/itensor_networks.md
@@ -23,7 +23,7 @@ indices:
 using Graphs: edges, ne, neighbors, nv, vertices
 using ITensorNetworks: ITensorNetwork, add, linkinds, siteinds
 using ITensors: Index, ITensor
-using NamedGraphs.NamedGraphGenerators: named_grid
+using NamedGraphs: named_grid
 
 i, j, k = Index(2, "i"), Index(2, "j"), Index(2, "k")
 A, B, C = ITensor(i, j), ITensor(j, k), ITensor(k)
@@ -39,8 +39,7 @@ indices on each edge, build the indices once per edge and reuse them at both end
 
 ```@example main
 using ITensors: random_itensor
-using NamedGraphs: NamedGraph
-using NamedGraphs.GraphsExtensions: edgetype, incident_edges
+using NamedGraphs: NamedGraph, edgetype, incident_edges
 
 g = NamedGraph(named_grid((3, 3)))
 s = siteinds("S=1/2", g)  # one spin-½ site Index per vertex

diff --git a/docs/src/solvers.md b/docs/src/solvers.md
@@ -20,8 +20,7 @@ using Graphs: vertices
 using ITensorNetworks:
     ITensorNetwork, TreeTensorNetwork, dmrg, dst, edges, normalize, siteinds, src
 using ITensors: Index, OpSum, random_itensor
-using NamedGraphs.GraphsExtensions: incident_edges
-using NamedGraphs.NamedGraphGenerators: named_comb_tree
+using NamedGraphs: incident_edges, named_comb_tree
 
 function random_state(g, s; link_space)
     l = Dict(e => Index(link_space, "Link") for e in edges(g))

diff --git a/docs/src/tree_tensor_networks.md b/docs/src/tree_tensor_networks.md
@@ -37,9 +37,7 @@ using ITensorNetworks: ITensorNetwork, TreeTensorNetwork, ortho_region, orthogon
     siteinds
 using ITensors: ITensors, Index, random_itensor
 using LinearAlgebra: norm
-using NamedGraphs: NamedGraph
-using NamedGraphs.GraphsExtensions: incident_edges
-using NamedGraphs.NamedGraphGenerators: named_comb_tree
+using NamedGraphs: NamedGraph, incident_edges, named_comb_tree
 
 # Comb-tree TTN (a popular tree topology for 2D-like systems)
 g = NamedGraph(named_comb_tree((3, 2)))

diff --git a/src/abstractindsnetwork.jl b/src/abstractindsnetwork.jl
@@ -3,9 +3,7 @@ using DataGraphs: DataGraphs, AbstractDataGraph, DataGraph, IsUnderlyingGraph, e
     set_edge_data!, set_vertex_data!, underlying_graph_type, vertex_data
 using Graphs: Graphs, AbstractEdge
 using ITensors: ITensors, Index, unioninds
-using NamedGraphs.GraphsExtensions:
-    GraphsExtensions, directed_graph, incident_edges, rename_vertices
-using NamedGraphs: NamedGraphs
+using NamedGraphs: NamedGraphs, directed_graph, incident_edges, rename_vertices
 
 abstract type AbstractIndsNetwork{V, I} <: AbstractDataGraph{V, Vector{I}, Vector{I}} end
 
@@ -14,7 +12,7 @@ data_graph(graph::AbstractIndsNetwork) = not_implemented()
 
 # Overload if needed
 Graphs.is_directed(::Type{<:AbstractIndsNetwork}) = false
-GraphsExtensions.directed_graph(is::AbstractIndsNetwork) = directed_graph(data_graph(is))
+NamedGraphs.directed_graph(is::AbstractIndsNetwork) = directed_graph(data_graph(is))
 
 # AbstractDataGraphs overloads
 DataGraphs.underlying_graph(is::AbstractIndsNetwork) = underlying_graph(data_graph(is))

diff --git a/src/abstractitensornetwork.jl b/src/abstractitensornetwork.jl
@@ -3,15 +3,14 @@ using DataGraphs:
     DataGraphs, set_vertex_data!, underlying_graph, underlying_graph_type, vertex_data
 using Dictionaries: Dictionaries, Dictionary
 using Graphs: Graphs, Graph, add_edge!, add_vertex!, bfs_tree, center, dst, edges, edgetype,
-    has_edge, ne, neighbors, rem_edge!, src, vertices
+    has_edge, ne, neighbors, rem_edge!, src, steiner_tree, vertices
 using ITensors: ITensors, ITensor, Index, addtags, commoninds, commontags, contract, dag,
     inds, noprime, onehot, prime, replaceprime, replacetags, setprime, settags, sim,
     swaptags, tags
 using LinearAlgebra: LinearAlgebra, qr, qr!
 using NDTensors: NDTensors, Algorithm, dim, scalartype
-using NamedGraphs.GraphsExtensions:
-    add_edges, directed_graph, incident_edges, rename_vertices, vertextype, ⊔
-using NamedGraphs: NamedGraphs, NamedGraph, Vertices, not_implemented, steiner_tree
+using NamedGraphs: NamedGraphs, NamedGraph, add_edges, directed_graph, incident_edges,
+    not_implemented, rename_vertices, vertextype, ⊔
 using SplitApplyCombine: flatten
 
 abstract type AbstractITensorNetwork{V} <: AbstractDataGraph{V, ITensor, ITensor} end
@@ -56,7 +55,7 @@ Base.eltype(tn::AbstractITensorNetwork) = eltype(vertex_data(tn))
 
 # Overload if needed
 Graphs.is_directed(::Type{<:AbstractITensorNetwork}) = false
-function GraphsExtensions.directed_graph(tn::AbstractITensorNetwork)
+function NamedGraphs.directed_graph(tn::AbstractITensorNetwork)
     return directed_graph(underlying_graph(tn))
 end
 
@@ -75,13 +74,6 @@ DataGraphs.is_edge_assigned(::AbstractITensorNetwork, _) = false
 
 DataGraphs.get_vertex_data(tn::AbstractITensorNetwork, v) = vertex_data(tn)[v]
 
-function NamedGraphs.vertex_positions(tn::AbstractITensorNetwork)
-    return NamedGraphs.vertex_positions(underlying_graph(tn))
-end
-function NamedGraphs.ordered_vertices(tn::AbstractITensorNetwork)
-    return NamedGraphs.ordered_vertices(underlying_graph(tn))
-end
-
 function Adapt.adapt_structure(to, tn::AbstractITensorNetwork)
     return map(adapt(to), tn)
 end
@@ -623,15 +615,15 @@ function add(tn1::AbstractITensorNetwork, tn2::AbstractITensorNetwork)
         length(linkinds(tn2, e)) > 1 && qr!(tn2, e)
     end
 
-    edges_tn1, edges_tn2 = edges(tn1), edges(tn2)
+    edges_tn1, edges_tn2 = collect(edges(tn1)), collect(edges(tn2))
 
     if !issetequal(edges_tn1, edges_tn2)
         new_edges = union(edges_tn1, edges_tn2)
         tn1 = add_edges(tn1, new_edges)
         tn2 = add_edges(tn2, new_edges)
     end
 
-    edges_tn1, edges_tn2 = edges(tn1), edges(tn2)
+    edges_tn1, edges_tn2 = collect(edges(tn1)), collect(edges(tn2))
     @assert issetequal(edges_tn1, edges_tn2)
 
     tn12 = copy(tn1)

diff --git a/src/caches/abstractbeliefpropagationcache.jl b/src/caches/abstractbeliefpropagationcache.jl
@@ -5,18 +5,16 @@ using Graphs: Graphs, IsDirected, dst, src
 using ITensors: dir
 using LinearAlgebra: diag, dot
 using NDTensors: NDTensors
-using NamedGraphs.GraphsExtensions: subgraph
 using NamedGraphs.PartitionedGraphs: PartitionedGraph, PartitionedGraphs, QuotientEdge,
     QuotientVertex, boundary_quotientedges, quotientedges, quotientvertices,
     unpartitioned_graph
-using NamedGraphs.SimilarType: SimilarType
-using NamedGraphs: to_graph_index
+using NamedGraphs: NamedGraphs, subgraph, to_graph_index
 using SimpleTraits: SimpleTraits, @traitfn, Not
 using SplitApplyCombine: group
 
 abstract type AbstractBeliefPropagationCache{V, PV} <: AbstractITensorNetwork{V} end
 
-function SimilarType.similar_type(bpc::AbstractBeliefPropagationCache)
+function NamedGraphs.similar_type(bpc::AbstractBeliefPropagationCache)
     return typeof(tensornetwork(bpc))
 end
 

diff --git a/src/contract.jl b/src/contract.jl
@@ -1,8 +1,7 @@
 using ITensors.NDTensors: @Algorithm_str, Algorithm, NDTensors, contract
 using ITensors: ITensor, scalar
 using LinearAlgebra: normalize!
-using NamedGraphs.OrdinalIndexing: th
-using NamedGraphs: NamedGraphs
+using NamedGraphs: decoded_vertex, encoded_vertex, to_graph_index
 
 function NDTensors.contract(tn::AbstractITensorNetwork; alg = "exact", kwargs...)
     return contract(Algorithm(alg), tn; kwargs...)
@@ -15,8 +14,10 @@ function NDTensors.contract(
         sequence = contraction_sequence(tn; contraction_sequence_kwargs...),
         kwargs...
     )
-    sequence_linear_index = deepmap(v -> NamedGraphs.vertex_positions(tn)[v], sequence)
-    ts = map(v -> tn[v], (1:nv(tn))th)
+    sequence_linear_index = deepmap(
+        v -> encoded_vertex(tn, to_graph_index(tn, v)), sequence
+    )
+    ts = map(code -> tn[decoded_vertex(tn, code)], 1:nv(tn))
     return contract(ts; sequence = sequence_linear_index, kwargs...)
 end
 

diff --git a/src/contraction_sequences.jl b/src/contraction_sequences.jl
@@ -1,8 +1,22 @@
-using Graphs: vertices
+using Graphs: nv, vertices
 using ITensors.NDTensors: @Algorithm_str, Algorithm
 using ITensors: ITensor
-using NamedGraphs.Keys: Key
-using NamedGraphs.OrdinalIndexing: th
+using NamedGraphs: NamedGraphs, decoded_vertex
+
+# A key (index) type, used for unambiguously identifying an object as a key or
+# index of an indexable object rather than as a container to descend into. That
+# distinction matters for the nested structure of a contraction sequence, whose
+# leaves are vertices that may themselves be containers:
+#
+#     [Key([1, 2]), [Key([3, 4]), Key([5, 6])]]
+struct Key{K}
+    I::K
+end
+Key(I...) = Key(I)
+
+Base.show(io::IO, I::Key) = print(io, "Key(", I.I, ")")
+
+NamedGraphs.to_graph_index(graph, key::Key) = key.I
 
 const ITensorList = Union{Vector{ITensor}, Tuple{Vararg{ITensor}}}
 
@@ -24,9 +38,8 @@ function deepmap(f, tree; filter = (x -> x isa AbstractArray))
 end
 
 function contraction_sequence(tn::AbstractITensorNetwork; kwargs...)
-    # TODO: Use `token_vertex` and/or `token_vertices` here.
-    ts = map(v -> tn[v], (1:nv(tn))th)
+    ts = map(code -> tn[decoded_vertex(tn, code)], 1:nv(tn))
     seq_linear_index = contraction_sequence(ts; kwargs...)
     # TODO: Use `Functors.fmap` or `StructWalk`?
-    return deepmap(n -> Key(vertices(tn)[n * th]), seq_linear_index)
+    return deepmap(code -> Key(decoded_vertex(tn, code)), seq_linear_index)
 end
diff --git a/src/edge_sequences.jl b/src/edge_sequences.jl
@@ -1,9 +1,8 @@
 using Graphs: IsDirected, connected_components, edges, edgetype
 using ITensors.NDTensors: @Algorithm_str, Algorithm
-using NamedGraphs.GraphsExtensions:
-    GraphsExtensions, forest_cover, subgraph, undirected_graph
 using NamedGraphs.PartitionedGraphs: PartitionedGraph, QuotientEdge, quotient_graph
-using NamedGraphs: NamedGraphs
+using NamedGraphs:
+    NamedGraphs, default_root_vertex, forest_cover, subgraph, undirected_graph
 using SimpleTraits: SimpleTraits, @traitfn, Not
 
 default_edge_sequence_alg() = "forest_cover"
@@ -32,7 +31,7 @@ end
 @traitfn function edge_sequence(
         ::Algorithm"forest_cover",
         g::::(!IsDirected);
-        root_vertex = GraphsExtensions.default_root_vertex
+        root_vertex = default_root_vertex
     )
     forests = forest_cover(g)
     edges = edgetype(g)[]
@@ -47,5 +46,6 @@ end
 end
 
 @traitfn function edge_sequence(::Algorithm"parallel", g::::(!IsDirected))
-    return [[e] for e in vcat(edges(g), reverse.(edges(g)))]
+    es = collect(edges(g))
+    return [[e] for e in vcat(es, reverse.(es))]
 end
diff --git a/src/formnetworks/abstractformnetwork.jl b/src/formnetworks/abstractformnetwork.jl
@@ -1,6 +1,6 @@
 using DataGraphs: DataGraphs, underlying_graph, vertex_data
 using Graphs: induced_subgraph
-using NamedGraphs.SimilarType: SimilarType
+using NamedGraphs: NamedGraphs
 
 default_bra_vertex_suffix() = "bra"
 default_ket_vertex_suffix() = "ket"
@@ -10,18 +10,18 @@ abstract type AbstractFormNetwork{V} <: AbstractITensorNetwork{V} end
 
 #Needed for interface
 dual_index_map(f::AbstractFormNetwork) = not_implemented()
-# TODO: Use `NamedGraphs.GraphsExtensions.parent_graph`.
+# TODO: Use `NamedGraphs.parent_graph`.
 tensornetwork(f::AbstractFormNetwork) = not_implemented()
 Base.copy(f::AbstractFormNetwork) = not_implemented()
 operator_vertex_suffix(f::AbstractFormNetwork) = not_implemented()
 bra_vertex_suffix(f::AbstractFormNetwork) = not_implemented()
 ket_vertex_suffix(f::AbstractFormNetwork) = not_implemented()
 
-function SimilarType.similar_type(f::AbstractFormNetwork)
+function NamedGraphs.similar_type(f::AbstractFormNetwork)
     return typeof(tensornetwork(f))
 end
 
-# TODO: Use `NamedGraphs.GraphsExtensions.parent_graph` / `parent_graph_type`.
+# TODO: Use `NamedGraphs.parent_graph` / `parent_graph_type`.
 DataGraphs.underlying_graph(f::AbstractFormNetwork) = underlying_graph(tensornetwork(f))
 DataGraphs.vertex_data(f::AbstractFormNetwork) = vertex_data(tensornetwork(f))
 

diff --git a/src/formnetworks/bilinearformnetwork.jl b/src/formnetworks/bilinearformnetwork.jl
@@ -2,7 +2,7 @@ using Adapt: adapt
 using DataGraphs: DataGraphs, set_vertex_data!
 using ITensors.NDTensors: datatype, denseblocks
 using ITensors: ITensor, Index, Op, dag, delta, prime, sim
-using NamedGraphs.GraphsExtensions: disjoint_union
+using NamedGraphs: disjoint_union
 
 default_dual_site_index_map = prime
 default_dual_link_index_map = sim
@@ -44,7 +44,7 @@ end
 operator_vertex_suffix(blf::BilinearFormNetwork) = blf.operator_vertex_suffix
 bra_vertex_suffix(blf::BilinearFormNetwork) = blf.bra_vertex_suffix
 ket_vertex_suffix(blf::BilinearFormNetwork) = blf.ket_vertex_suffix
-# TODO: Use `NamedGraphs.GraphsExtensions.parent_graph`.
+# TODO: Use `NamedGraphs.parent_graph`.
 tensornetwork(blf::BilinearFormNetwork) = blf.tensornetwork
 
 # Forward vertex writes to the wrapped network so reverse-index map and

diff --git a/src/formnetworks/linearformnetwork.jl b/src/formnetworks/linearformnetwork.jl
@@ -1,6 +1,6 @@
 using DataGraphs: DataGraphs, set_vertex_data!
 using ITensors: ITensor, dag, prime
-using NamedGraphs.GraphsExtensions: disjoint_union
+using NamedGraphs: disjoint_union
 
 default_dual_link_index_map = prime
 
@@ -36,7 +36,7 @@ end
 
 bra_vertex_suffix(lf::LinearFormNetwork) = lf.bra_vertex_suffix
 ket_vertex_suffix(lf::LinearFormNetwork) = lf.ket_vertex_suffix
-# TODO: Use `NamedGraphs.GraphsExtensions.parent_graph`.
+# TODO: Use `NamedGraphs.parent_graph`.
 tensornetwork(lf::LinearFormNetwork) = lf.tensornetwork
 
 # Forward vertex writes to the wrapped network so reverse-index map and

diff --git a/src/indsnetwork.jl b/src/indsnetwork.jl
@@ -4,9 +4,8 @@ using Dictionaries: AbstractDictionary, Dictionary, Indices
 using Graphs.SimpleGraphs: AbstractSimpleGraph
 using Graphs: Graphs
 using ITensors: Index, QN, dag
-using NamedGraphs.GraphsExtensions: vertextype
-using NamedGraphs.NamedGraphGenerators: named_path_graph
-using NamedGraphs: NamedGraphs, AbstractNamedGraph, NamedEdge, NamedGraph
+using NamedGraphs:
+    NamedGraphs, AbstractNamedGraph, NamedEdge, NamedGraph, named_path_graph, vertextype
 using SimpleTraits: SimpleTraits, @traitfn, Not
 
 # Spaces accepted by `Index`: a plain `Integer` dimension (dense) or a QN-block
-Original file line number
+Diff line change
@@ Expand Up / @@ -49,6 +49,7 @@ makedocs(; @@
                 "Deprecated Methods" => "deprecated_methods.md",
             ],
             "API Reference" => "reference.md",
+            "Changelog" => "changelog.md",
         ]
     )
@@ Expand Down @@