Add evaluation order optimization

Author: mtfishman

Project.toml

@@ -7,6 +7,7 @@ version = "0.1.15"
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
 BackendSelection = "680c2d7c-f67a-4cc9-ae9c-da132b1447a5"
+Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
 DataGraphs = "b5a273c3-7e6c-41f6-98bd-8d7f1525a36a"
 DiagonalArrays = "74fd4be6-21e2-4f6f-823a-4360d37c7a77"
 Dictionaries = "85a47980-9c8c-11e8-2b9f-f7ca1fa99fb4"
@@ -31,6 +32,7 @@ ITensorNetworksNextTensorOperationsExt = "TensorOperations"
 AbstractTrees = "0.4.5"
 Adapt = "4.3"
 BackendSelection = "0.1.6"
+Combinatorics = "1.0.3"
 DataGraphs = "0.2.7"
 DiagonalArrays = "0.3.23"
 Dictionaries = "0.4.5"