update 3-arg logdensity (#10)

* update 3-arg logdensity

* small warning update

* add test

* bump version

* drop unused code

Author: cscherrer

Project.toml

@@ -1,7 +1,7 @@
 name = "MeasureBase"
 uuid = "fa1605e6-acd5-459c-a1e6-7e635759db14"
 authors = ["Chad Scherrer <[email protected]> and contributors"]
-version = "0.3.5"
+version = "0.3.6"
 
 [deps]
 ConcreteStructs = "2569d6c7-a4a2-43d3-a901-331e8e4be471"

src/MeasureBase.jl

@@ -1,5 +1,6 @@
 module MeasureBase
 
+const logtwo = log(2.0)
 
 using Random
 

src/density.jl

@@ -107,21 +107,22 @@ function logdensity(μ::AbstractMeasure, ν::AbstractMeasure, x)
     α = basemeasure(μ)
     β = basemeasure(ν)
 
-    ℓμ = @trysupport logdensity(μ, x)
-    ℓν = @trysupport logdensity(ν, x)
-
-    if α==μ && β==ν
+    if α===μ && β===ν
         @warn """
         No method found for logdensity(μ, ν, x) where
-        μ == $μ
-        ν == $ν
+        typeof(μ) == $(typeof(μ))
+        typeof(ν) == $(typeof(ν))
 
-        Assuming logdensity of 0.0
+        Returning NaN. If this is incorrect, please add a method        
+        logdensity(μ::$(typeof(μ)), ν::$(typeof(ν)), x)
         """
-        return ℓμ - ℓν
+        return NaN
     end
-        
-    ℓμ - ℓν + logdensity(α, β, x)
+
+    ℓμ = logdensity(μ, x)
+    ℓν = logdensity(ν, x)
+
+    return ℓμ - ℓν + logdensity(α, β, x)
 end
 
 logdensity(::Lebesgue, ::Lebesgue, x) = 0.0

src/utils.jl

@@ -25,17 +25,6 @@ constructor(::T) where {T} = constructor(T)
 
 constructor(::Type{T}) where {T} = constructorof(T)
 
-macro trysupport(ex)
-    ex = esc(ex)
-    quote
-        try
-            return $ex
-        catch 
-            return -Inf
-        end
-    end
-end
-
 export testvalue
 testvalue(μ::AbstractMeasure) = testvalue(basemeasure(μ))
 

test/runtests.jl

@@ -156,6 +156,9 @@ end
     @half Normal
     @test logdensity(HalfNormal(), -0.2) == -Inf
     @test logdensity(HalfNormal(), 0.2) == logdensity(Normal(), 0.2)
+    
+    @half Lebesgue
+    @test basemeasure(HalfLebesgue(ℝ)) == 2 * Lebesgue(ℝ)
 end
 
 # import MeasureBase.:⋅