GraphsFlows extension

Project.toml

@@ -13,7 +13,6 @@ Dictionaries = "85a47980-9c8c-11e8-2b9f-f7ca1fa99fb4"
 Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
 Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
-GraphsFlows = "06909019-6f44-4949-96fc-b9d9aaa02889"
 ITensors = "9136182c-28ba-11e9-034c-db9fb085ebd5"
 IsApprox = "28f27b66-4bd8-47e7-9110-e2746eb8bed7"
 IterTools = "c8e1da08-722c-5040-9ed9-7db0dc04731e"
@@ -36,11 +35,13 @@ TupleTools = "9d95972d-f1c8-5527-a6e0-b4b365fa01f6"
 
 [weakdeps]
 EinExprs = "b1794770-133b-4de1-afb4-526377e9f4c5"
+GraphsFlows = "06909019-6f44-4949-96fc-b9d9aaa02889"
 Observers = "338f10d5-c7f1-4033-a7d1-f9dec39bcaa0"
 OMEinsumContractionOrders = "6f22d1fd-8eed-4bb7-9776-e7d684900715"
 
 [extensions]
 ITensorNetworksEinExprsExt = "EinExprs"
+ITensorNetworksGraphsFlowsExt = "GraphsFlows"
 ITensorNetworksObserversExt = "Observers"
 ITensorNetworksOMEinsumContractionOrdersExt = "OMEinsumContractionOrders"
 
@@ -78,6 +79,7 @@ julia = "1.10"
 
 [extras]
 EinExprs = "b1794770-133b-4de1-afb4-526377e9f4c5"
+GraphsFlows = "06909019-6f44-4949-96fc-b9d9aaa02889"
 Observers = "338f10d5-c7f1-4033-a7d1-f9dec39bcaa0"
 OMEinsumContractionOrders = "6f22d1fd-8eed-4bb7-9776-e7d684900715"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

ext/ITensorNetworksGraphsFlowsExt/ITensorNetworksGraphsFlowsExt.jl

@@ -0,0 +1,19 @@
+module ITensorNetworksGraphsFlowsExt
+using Graphs: AbstractGraph
+using GraphsFlows: GraphsFlows
+using ITensorNetworks: ITensorNetworks
+using NDTensors.AlgorithmSelection: @Algorithm_str
+
+function ITensorNetworks.mincut(
+  ::Algorithm"GraphsFlows",
+  graph::AbstractGraph,
+  source_vertex,
+  target_vertex;
+  capacity_matrix,
+  alg=GraphsFlows.PushRelabelAlgorithm(),
+)
+  # TODO: Replace with `Backend(backend)`.
+  return GraphsFlows.mincut(graph, source_vertex, target_vertex, capacity_matrix, alg)
+end
+
+end

src/contract_approx/mincut.jl

@@ -1,8 +1,8 @@
 using AbstractTrees: Leaves, PostOrderDFS
 using Combinatorics: powerset
 using Graphs: dijkstra_shortest_paths, weights
-using GraphsFlows: GraphsFlows
 using NamedGraphs: NamedDiGraph
+using NDTensors.AlgorithmSelection: Algorithm
 
 # a large number to prevent this edge being a cut
 MAX_WEIGHT = 1e32
@@ -37,6 +37,18 @@ function binary_tree_structure(tn::ITensorNetwork, outinds::Vector)
   return _binary_tree_structure(tn, outinds; maximally_unbalanced=false)
 end
 
+function mincut(graph::AbstractGraph, source_vertex, target_vertex; backend, kwargs...)
+  # TODO: Replace with `Backend(backend)`.
+  return mincut(Algorithm(backend), graph, source_vertex, target_vertex; kwargs...)
+end
+
+# TODO: Replace with `backend::Backend`.
+function mincut(
+  backend::Algorithm, graph::AbstractGraph, source_vertex, target_vertex; kwargs...
+)
+  return error("Backend `$backend` not implemented for `mincut`.")
+end
+
 """
 Calculate the mincut between two subsets of the uncontracted inds
 (source_inds and terminal_inds) of the input tn.
@@ -52,7 +64,7 @@ function _mincut(tn::ITensorNetwork, source_inds::Vector, terminal_inds::Vector)
   tn = disjoint_union(
     ITensorNetwork([ITensor(source_inds...), ITensor(terminal_inds...)]), tn
   )
-  return GraphsFlows.mincut(tn, (1, 1), (2, 1), weights(tn))
+  return mincut(tn, (1, 1), (2, 1); backend="GraphsFlows", capacity_matrix=weights(tn))
 end
 
 """