New: implement findmax and findmin interfaces

Project.toml

@@ -1,7 +1,7 @@
 name = "GenericTensorNetworks"
 uuid = "3521c873-ad32-4bb4-b63d-f4f178f42b49"
 authors = ["GiggleLiu <[email protected]> and contributors"]
-version = "3.0.0"
+version = "3.1.0"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"

src/GenericTensorNetworks.jl

@@ -67,6 +67,9 @@ export SetCovering, is_set_covering
 # Interfaces
 export solve, SizeMax, SizeMin, PartitionFunction, CountingAll, CountingMax, CountingMin, GraphPolynomial, SingleConfigMax, SingleConfigMin, ConfigsAll, ConfigsMax, ConfigsMin, Single, AllConfigs
 
+# ProblemReductions API
+export GTNSolver
+
 # Utilities
 export save_configs, load_configs, hamming_distribution, save_sumproduct, load_sumproduct
 

src/interfaces.jl

@@ -483,3 +483,18 @@ for GP in [:IndependentSet, :MaxCut, :DominatingSet, :Satisfiability, :Coloring,
 end
 size_all_negative(::SpinGlass) = false
 size_all_positive(::SpinGlass) = false
+
+# NOTE: `findmin` and `findmax` are required by `ProblemReductions.jl`
+Base.@kwdef struct GTNSolver
+    optimizer::OMEinsum.CodeOptimizer = TreeSA()
+    usecuda::Bool = false
+    T::Type = Float64
+end
+function Base.findmin(problem::AbstractProblem, solver::GTNSolver)
+    res = collect(solve(GenericTensorNetwork(problem; optimizer=solver.optimizer), ConfigsMin(; tree_storage=true); usecuda=solver.usecuda, T=solver.T)[].c)
+    return map(x -> ProblemReductions.id_to_config(problem, Int.(x) .+ 1), res)
+end
+function Base.findmax(problem::AbstractProblem, solver::GTNSolver)
+    res = collect(solve(GenericTensorNetwork(problem; optimizer=solver.optimizer), ConfigsMax(; tree_storage=true); usecuda=solver.usecuda, T=solver.T)[].c)
+    return map(x -> ProblemReductions.id_to_config(problem, Int.(x) .+ 1), res)
+end

test/interfaces.jl

@@ -1,4 +1,4 @@
-using GenericTensorNetworks
+using GenericTensorNetworks, GenericTensorNetworks.ProblemReductions
 using Graphs, Test, Random
 
 @testset "independent set problem" begin
@@ -245,4 +245,12 @@ end
     @test_throws ArgumentError solve(gp, ConfigsMin(2))
     @test solve(gp, ConfigsMin(Single)) isa Array
     @test_throws AssertionError ConfigsMin(0)
-end
+end
+
+@testset "GTNSolver" begin
+    sg = SpinGlass(smallgraph(:petersen), rand(15), rand(10))
+    solver1 = GTNSolver(; optimizer=TreeSA(ntrials=1))
+    solver2 = BruteForce()
+    @test Set(findmin(sg, solver1)) == Set(findmin(sg, solver2))
+    @test Set(findmax(sg, solver1)) == Set(findmax(sg, solver2))
+end