Working BP Commit

Author: JoeyT1994

src/ITensorNetworksNext.jl

@@ -3,4 +3,7 @@ module ITensorNetworksNext
 include("abstracttensornetwork.jl")
 include("tensornetwork.jl")
 
+include("beliefpropagation/abstractbeliefpropagationcache.jl")
+include("beliefpropagation/beliefpropagationcache.jl")
+
 end

src/abstracttensornetwork.jl

@@ -276,4 +276,4 @@ function Base.show(io::IO, mime::MIME"text/plain", graph::AbstractTensorNetwork)
   return nothing
 end
 
-Base.show(io::IO, graph::AbstractTensorNetwork) = show(io, MIME"text/plain"(), graph)
+Base.show(io::IO, graph::AbstractTensorNetwork) = show(io, MIME"text/plain"(), graph)

test/test_beliefpropagation.jl

@@ -0,0 +1,25 @@
+using Dictionaries: Dictionary
+using ITensorBase: Index
+using ITensorNetworksNext: ITensorNetworksNext, BeliefPropagationCache, TensorNetwork, adapt_messages, default_message, default_messages, edge_scalars, messages, setmessages!, factors, freenergy,
+  partitionfunction
+using Graphs: edges, vertices
+using NamedGraphs.NamedGraphGenerators: named_grid
+using NamedGraphs.GraphsExtensions: arranged_edges, incident_edges
+using Test: @test, @testset
+
+@testset "BeliefPropagation" begin
+    dims = (4, 1)
+    g = named_grid(dims)
+    l = Dict(e => Index(2) for e in edges(g))
+    l = merge(l, Dict(reverse(e) => l[e] for e in edges(g)))
+    tn = TensorNetwork(g) do v
+      is = map(e -> l[e], incident_edges(g, v))
+      return randn(Tuple(is))
+    end
+
+    bpc = BeliefPropagationCache(tn)
+    bpc = ITensorNetworksNext.update(bpc; maxiter = 10)
+    z_bp = partitionfunction(bpc)
+    z_exact = reduce(*, [tn[v] for v in vertices(g)])[]
+    @test abs(z_bp - z_exact) <= 1e-14
+end