Make integers fixed (#3)

* Make integers not flattenable

* Bump patch

* Update README

* Tweak README

Co-authored-by: wt <[email protected]>

Project.toml

@@ -1,7 +1,7 @@
 name = "ParameterHandling"
 uuid = "2412ca09-6db7-441c-8e3a-88d5709968c5"
 authors = ["Invenia Technical Computing Corporation"]
-version = "0.1.0"
+version = "0.1.1"
 
 [deps]
 Bijectors = "76274a88-744f-5084-9051-94815aaf08c4"

README.md

@@ -167,3 +167,9 @@ julia> value(unflatten(new_v)) # Obtain constrained value.
 It is straightforward to implement your own parameters that interoperate with those already
 written by implementing `value` and `flatten` for them. You might want to do this if this
 package doesn't currently support the functionality that you need.
+
+
+
+# Gotchas
+
+1. `Integer`s typically don't take part in the kind of optimisation procedures that this package is designed to handle. Consequently, `flatten(::Integer)` produces an empty vector.

src/flatten.jl

@@ -17,13 +17,19 @@ true
 """
 function flatten end
 
-function flatten(x::Real)
+function flatten(x::Integer)
+    v = Float64[]
+    unflatten_Integer(v::Vector{Float64}) = x
+    return v, unflatten_Integer
+end
+
+function flatten(x::AbstractFloat)
     v = [x]
     unflatten_to_Real(v::Vector{<:Real}) = only(v)
     return v, unflatten_to_Real
 end
 
-flatten(x::Vector{<:Real}) = (x, identity)
+flatten(x::Vector{<:AbstractFloat}) = (x, identity)
 
 function flatten(x::AbstractVector)
     x_vecs_and_backs = map(flatten, x)

test/flatten.jl

@@ -2,6 +2,11 @@
 
     @testset "Reals" begin
         test_flatten_interface(1.0)
+
+        @testset "Integers" begin
+            test_flatten_interface(1)
+            @test isempty(first(flatten(1)))
+        end
     end
 
     @testset "AbstractArrays" begin