From 329c0e4b81a90e91ce41ed95492c1073159ca59f Mon Sep 17 00:00:00 2001
From: Matthew Fishman <mfishman@flatironinstitute.org>
Date: Tue, 30 Jun 2026 09:56:22 -0400
Subject: [PATCH 1/2] Map IndexName to Int for contraction

---
 Project.toml | 8 ++++++--
 src/index.jl | 6 ++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/Project.toml b/Project.toml
index b34ba28..83ba76c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "ITensorBase"
 uuid = "4795dd04-0d67-49bb-8f44-b89c448a1dc7"
-version = "0.9.0"
+version = "0.9.1"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
 
 [workspace]
@@ -31,6 +31,10 @@ BlockArrays = "8e7c35d0-a365-5155-bbbb-fb81a777f24e"
 Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 TensorOperations = "6aa20fa7-93e2-5fca-9bc0-fbd0db3c71a2"
 
+[sources.TensorAlgebra]
+rev = "mf/contract-int-labels"
+url = "https://github.com/ITensor/TensorAlgebra.jl"
+
 [extensions]
 ITensorBaseAdaptExt = "Adapt"
 ITensorBaseBlockArraysExt = "BlockArrays"
@@ -52,7 +56,7 @@ Mooncake = "0.4.202, 0.5"
 OrderedCollections = "1.6"
 Random = "1.10"
 SimpleTraits = "0.9.4"
-TensorAlgebra = "0.12.4, 0.13"
+TensorAlgebra = "0.13.4"
 TensorOperations = "5.3.1"
 TermInterface = "2"
 TupleTools = "1.6"
diff --git a/src/index.jl b/src/index.jl
index d65e591..a709c64 100644
--- a/src/index.jl
+++ b/src/index.jl
@@ -1,5 +1,6 @@
 using Accessors: @set
 using Random: AbstractRNG, RandomDevice
+using TensorAlgebra: TensorAlgebra as TA
 using UUIDs: UUID, uuid4
 
 tagpairstring(pair::Pair) = string(first(pair)) * "=>" * string(last(pair))
@@ -39,6 +40,11 @@ function uniquename(rng::AbstractRNG, ::Type{<:IndexName})
     return IndexName(rng)
 end
 
+# Derive contractions on integer labels: an `IndexName` carries an id and a tag dictionary and is
+# far costlier to compare than an integer, and deriving a contraction makes several comparison
+# passes over the labels. See `TensorAlgebra.label_type`.
+TA.label_type(::Type{<:IndexName}) = Int
+
 to_symbol_pair(p::Pair) = Symbol(first(p)) => Symbol(last(p))
 
 # Like `Dict`, accept one or more bare `Pair`s as tags. A `Pair` iterates over

From 6e5eb1abbb688cc2154229cd8e903ca75f1a2d3c Mon Sep 17 00:00:00 2001
From: Matthew Fishman <mfishman@flatironinstitute.org>
Date: Tue, 30 Jun 2026 10:40:35 -0400
Subject: [PATCH 2/2] Remove the TensorAlgebra [sources] pin

---
 Project.toml | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/Project.toml b/Project.toml
index 83ba76c..537dc3d 100644
--- a/Project.toml
+++ b/Project.toml
@@ -31,10 +31,6 @@ BlockArrays = "8e7c35d0-a365-5155-bbbb-fb81a777f24e"
 Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 TensorOperations = "6aa20fa7-93e2-5fca-9bc0-fbd0db3c71a2"
 
-[sources.TensorAlgebra]
-rev = "mf/contract-int-labels"
-url = "https://github.com/ITensor/TensorAlgebra.jl"
-
 [extensions]
 ITensorBaseAdaptExt = "Adapt"
 ITensorBaseBlockArraysExt = "BlockArrays"