Merge #113

113: Add convenience functions r=devmotion a=devmotion

Fixes #112.

Co-authored-by: David Widmann <[email protected]>

Author: bors[bot]

src/DynamicPPL.jl

@@ -90,7 +90,14 @@ export  AbstractVarInfo,
         NoDist,
 # Prob macros
         @prob_str,
-        @logprob_str
+        @logprob_str,
+# Convenience functions
+        logprior,
+        logjoint
+
+# Reexport
+using Distributions: loglikelihood
+export loglikelihood
 
 const DEBUG = Bool(parse(Int, get(ENV, "DEBUG_DYNAMICPPL", "0")))
 

src/model.jl

@@ -183,3 +183,39 @@ getmissing(model::Model) = getmissings(model)
 Get the model generator associated with `model`.
 """
 getgenerator(model::Model) = model.modelgen
+
+"""
+    logjoint(model::Model, varinfo::AbstractVarInfo)
+
+Return the log joint probability of variables `varinfo` for the probabilistic `model`.
+
+See [`logjoint`](@ref) and [`loglikelihood`](@ref).
+"""
+function logjoint(model::Model, varinfo::AbstractVarInfo)
+    model(varinfo, SampleFromPrior(), DefaultContext())
+	  return getlogp(varinfo)
+end
+
+"""
+    logprior(model::Model, varinfo::AbstractVarInfo)
+
+Return the log prior probability of variables `varinfo` for the probabilistic `model`.
+
+See also [`logjoint`](@ref) and [`loglikelihood`](@ref).
+"""
+function logprior(model::Model, varinfo::AbstractVarInfo)
+    model(varinfo, SampleFromPrior(), PriorContext())
+	  return getlogp(varinfo)
+end
+
+"""
+    loglikelihood(model::Model, varinfo::AbstractVarInfo)
+
+Return the log likelihood of variables `varinfo` for the probabilistic `model`.
+
+See also [`logjoint`](@ref) and [`logprior`](@ref).
+"""
+function Distributions.loglikelihood(model::Model, varinfo::AbstractVarInfo)
+    model(varinfo, SampleFromPrior(), LikelihoodContext())
+	  return getlogp(varinfo)
+end

src/prob_macro.jl

@@ -175,7 +175,7 @@ end
 
 warn_msg(arg) = "Argument $arg is not defined. A value of `nothing` is used."
 
-function loglikelihood(
+function Distributions.loglikelihood(
     left::NamedTuple,
     right::NamedTuple,
     modelgen::ModelGen,

test/model.jl

@@ -0,0 +1,29 @@
+Random.seed!(1234)
+
+@testset "model.jl" begin
+    @testset "convenience functions" begin
+        model = gdemo_default
+
+        # sample from model and extract variables
+        vi = VarInfo(model)
+        model(vi, SampleFromPrior())
+        s = vi[@varname(s)]
+        m = vi[@varname(m)]
+
+        # extract log pdf of variable object
+        lp = getlogp(vi)
+
+        # log prior probability
+        lprior = logprior(model, vi)
+        @test lprior ≈ logpdf(InverseGamma(2, 3), s) + logpdf(Normal(0, sqrt(s)), m)
+
+        # log likelihood
+        llikelihood = loglikelihood(model, vi)
+        @test llikelihood ≈ loglikelihood(Normal(m, sqrt(s)), [1.5, 2.0])
+
+        # log joint probability
+        ljoint = logjoint(model, vi)
+        @test ljoint ≈ lprior + llikelihood
+        @test ljoint ≈ lp
+    end
+end

test/runtests.jl

@@ -13,12 +13,14 @@ using .Turing
 
 turnprogress(false)
 
+include("test_utils/AllUtils.jl")
 include("test_util.jl")
 
 @testset "DynamicPPL.jl" begin
     include("utils.jl")
     include("compiler.jl")
     include("varinfo.jl")
+    include("model.jl")
     include("sampler.jl")
     include("prob_macro.jl")
     include("independence.jl")