add load tn from code (#90)

Author: ArrogantGao

src/Core.jl

@@ -175,6 +175,21 @@ function TensorNetworkModel(
     TensorNetworkModel(collect(LT, vars), code, tensors, evidence, mars)
 end
 
+"""
+$(TYPEDSIGNATURES)
+"""
+function TensorNetworkModel(
+    model::UAIModel{T}, code;
+    evidence = Dict{Int,Int}(),
+    mars = [[i] for i=1:model.nvars],
+    vars = [1:model.nvars...]
+)::TensorNetworkModel where{T}
+    @debug "constructing tensor network model from code"
+    tensors = Array{T}[[ones(T, [model.cards[i] for i in mar]...) for mar in mars]..., [t.vals for t in model.factors]...]
+
+    return TensorNetworkModel(vars, code, tensors, evidence, mars)
+end
+
 """
 $(TYPEDSIGNATURES)
 

test/map.jl

@@ -2,6 +2,18 @@ using Test
 using OMEinsum
 using TensorInference
 
+@testset "load from code" begin
+    model = problem_from_artifact("uai2014", "MAR", "Promedus", 14)
+
+    tn1 = TensorNetworkModel(read_model(model);
+        evidence=read_evidence(model),
+        optimizer = TreeSA(ntrials = 3, niters = 2, βs = 1:0.1:80))
+    
+    tn2 = TensorNetworkModel(read_model(model), tn1.code, evidence=read_evidence(model))
+
+    @test tn1.code == tn2.code
+end
+
 @testset "gradient-based tensor network solvers" begin
     model = problem_from_artifact("uai2014", "MAR", "Promedus", 14)