Remove collect

[sklan]

Solves #657

julia> xs = param([1, 2, 3])
Tracked 3-element Array{Float64,1}:
 1.0
 2.0
 3.0

julia> collect(xs)
3-element Array{Flux.Tracker.TrackedReal{Float64},1}:
 1.0
 2.0
 3.0

[MikeInnes]

Can you add a definition for collect that just returns x? Keeping this as a TrackedArray is more efficient.

[sklan]

Yeah, sure. I'll do that.

[sklan]

@MikeInnes It still keeps calling the Base.collect

julia> xs = param([1, 2, 3])
Tracked 3-element Array{Float64,1}:
 1.0
 2.0
 3.0

julia> collect(xs)
3-element Array{Flux.Tracker.TrackedReal{Float64},1}:
 1.0
 2.0
 3.0

julia> @which collect(xs)
collect(A::AbstractArray) in Base at array.jl:546

I am confused. Am I missing something?

[MikeInnes]

You need to define Base.collect (otherwise it creates a new function, Flux.collect).

[MikeInnes]

Unfortunately this got caught when we split out Tracker.jl. You should be able to easily PR the same branch against that repo, though.

[sklan]

Okay, I'll add a PR in Tracker.jl.