Primitive implementation for serialization (#258)

Project.toml

@@ -1,6 +1,6 @@
 name = "JuliaBUGS"
 uuid = "ba9fb4c0-828e-4473-b6a1-cd2560fee5bf"
-version = "0.7.5"
+version = "0.8.0"
 
 [deps]
 AbstractMCMC = "80f14c24-f653-4e6a-9b94-39d6b0f70001"
@@ -22,6 +22,7 @@ MetaGraphsNext = "fa8bd995-216d-47f1-8a91-f3b68fbeb377"
 OrderedCollections = "bac558e1-5e72-5ebc-8fee-abe8a469f55d"
 PDMats = "90014a1f-27ba-587c-ab20-58faa44d9150"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+Serialization = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
@@ -67,6 +68,7 @@ MacroTools = "0.5"
 MetaGraphsNext = "0.6, 0.7"
 OrderedCollections = "1"
 PDMats = "0.10, 0.11"
+Serialization = "1.9.0"
 SpecialFunctions = "2"
 StaticArrays = "1.9"
 Statistics = "1.9"

src/JuliaBUGS.jl

@@ -12,6 +12,7 @@ using LogDensityProblems, LogDensityProblemsAD
 using MacroTools
 using OrderedCollections: OrderedDict
 using Random
+using Serialization: Serialization
 using StaticArrays
 
 import Base: ==, hash, Symbol, size
@@ -172,7 +173,7 @@ function compile(model_def::Expr, data::NamedTuple, initial_params::NamedTuple=N
             values(eval_env),
         ),
     )
-    return BUGSModel(g, nonmissing_eval_env, initial_params)
+    return BUGSModel(g, nonmissing_eval_env, model_def, data, initial_params)
 end
 
 """

src/model.jl

@@ -48,8 +48,9 @@ end
 The `BUGSModel` object is used for inference and represents the output of compilation. It implements the
 [`LogDensityProblems.jl`](https://github.com/tpapp/LogDensityProblems.jl) interface.
 """
-struct BUGSModel{base_model_T<:Union{<:AbstractBUGSModel,Nothing},T<:NamedTuple,TNF,TV} <:
-       AbstractBUGSModel
+struct BUGSModel{
+    base_model_T<:Union{<:AbstractBUGSModel,Nothing},T<:NamedTuple,TNF,TV,data_T
+} <: AbstractBUGSModel
     " Indicates whether the model parameters are in the transformed space. "
     transformed::Bool
 
@@ -74,6 +75,10 @@ struct BUGSModel{base_model_T<:Union{<:AbstractBUGSModel,Nothing},T<:NamedTuple,
 
     "If not `Nothing`, the model is a conditioned model; otherwise, it's the model returned by `compile`."
     base_model::base_model_T
+
+    # for serialization, save the original model definition and data
+    model_def::Expr
+    data::data_T
 end
 
 function Base.show(io::IO, model::BUGSModel)
@@ -137,7 +142,9 @@ variables(model::BUGSModel) = collect(labels(model.g))
 function BUGSModel(
     g::BUGSGraph,
     evaluation_env::NamedTuple,
-    initial_params::NamedTuple=NamedTuple();
+    model_def::Expr,
+    data::NamedTuple,
+    initial_params::NamedTuple=NamedTuple(),
     is_transformed::Bool=true,
 )
     flattened_graph_node_data = FlattenedGraphNodeData(g)
@@ -199,6 +206,8 @@ function BUGSModel(
         flattened_graph_node_data,
         g,
         nothing,
+        model_def,
+        data,
     )
 end
 
@@ -220,9 +229,31 @@ function BUGSModel(
         FlattenedGraphNodeData(g, sorted_nodes),
         g,
         isnothing(model.base_model) ? model : model.base_model,
+        model.model_def,
+        model.data,
     )
 end
 
+function Serialization.serialize(s::Serialization.AbstractSerializer, model::BUGSModel)
+    Serialization.writetag(s.io, Serialization.OBJECT_TAG)
+    Serialization.serialize(s, typeof(model))
+    Serialization.serialize(s, model.transformed)
+    Serialization.serialize(s, model.model_def)
+    Serialization.serialize(s, model.data)
+    Serialization.serialize(s, model.evaluation_env)
+    return nothing
+end
+
+function Serialization.deserialize(s::Serialization.AbstractSerializer, ::Type{<:BUGSModel})
+    model_def = Serialization.deserialize(s)
+    data = Serialization.deserialize(s)
+    evaluation_env = Serialization.deserialize(s)
+    transformed = Serialization.deserialize(s)
+    # use evaluation_env as initialization to restore the values
+    model = compile(model_def, data, evaluation_env)
+    return settrans(model, transformed)
+end
+
 """
     initialize!(model::BUGSModel, initial_params::NamedTuple)
 

test/model.jl

@@ -1,3 +1,32 @@
+@testset "serialization" begin
+    (; model_def, data) = JuliaBUGS.BUGSExamples.rats
+    model = compile(model_def, data)
+    serialize("m.jls", model)
+    deserialized = deserialize("m.jls")
+    @testset "test values are correctly restored" begin
+        for vn in MetaGraphsNext.labels(model.g)
+            @test isequal(
+                get(model.evaluation_env, vn), get(deserialized.evaluation_env, vn)
+            )
+        end
+
+        @test model.transformed == deserialized.transformed
+        @test model.untransformed_param_length == deserialized.untransformed_param_length
+        @test model.transformed_param_length == deserialized.transformed_param_length
+        @test all(
+            model.untransformed_var_lengths[k] == deserialized.untransformed_var_lengths[k]
+            for k in keys(model.untransformed_var_lengths)
+        )
+        @test all(
+            model.transformed_var_lengths[k] == deserialized.transformed_var_lengths[k] for
+            k in keys(model.transformed_var_lengths)
+        )
+        @test Set(model.parameters) == Set(deserialized.parameters)
+        # skip testing g
+        @test model.model_def === deserialized.model_def
+    end
+end
+
 @testset "controlling sampling behavior for conditioned variables" begin
     model_def = @bugs begin
         x ~ Normal(0, 1)

test/runtests.jl

@@ -21,6 +21,7 @@ using MacroTools
 using MCMCChains
 using Random
 using ReverseDiff
+using Serialization
 
 AbstractMCMC.setprogress!(false)