conversions for dual numbers

src/tracker/lib/real.jl

@@ -99,6 +99,12 @@ import Base:^
 
 ^(a::TrackedReal, b::Integer) = track(^, a, b)
 
+# Hack for conversions
+
+using ForwardDiff: Dual
+
+(T::Type{<:Real})(x::Dual) = Dual(T(x.value), map(T, x.partials.values))
+
 # Tuples
 
 struct TrackedTuple{T<:Tuple}

test/tracker.jl

@@ -189,6 +189,8 @@ end
 @test gradtest(x -> meanpool(x, (2,2)), rand(10, 10, 3, 2))
 @test gradtest(x -> meanpool(x, (2,2,2)), rand(5, 5, 5, 3, 2))
 
+@test gradtest(x -> Float64.(x), 5)
+
 @testset "equality & order" begin
     # TrackedReal
     @test param(2)^2 == param(4)