I was going through this Flux.jl tutorial and came across something called Chain.
m = Chain(Dense(10, 5, relu), Dense(5, 2), softmax)
It was not imported from any of the used modules and no namespace was used, so I did not know which module it belonged to. Although I managed to find that I belongs to Flux package, I wonder if there is a general way of figuring this out within the script.
To figure out where a specific function comes from, you can use the parentmodule function:
julia> parentmodule(Chain)
Flux
Read more in the Julia docs: https://docs.julialang.org/en/v1/base/base/#Base.parentmodule
Note that, as the docs mention, parentmodule(<function>) only returns the module containing the first definition of the function, which may not necessarily be the one we care about. In this case it doesn't matter since Chain has definitions only in Flux, but sometimes a function has definitions in multiple packages, and which one applies depends on the type of the arguments.
parentmodule could help you there too, if you pass it the types of your arguments (for eg. parentmodule(Chain, (Dense, Dense, Function)) here), but I generally just tend to use the @which macro:
julia> @which Chain(Dense(10, 5, relu), Dense(5, 2), softmax)
Chain(xs...) in Flux at /home/Sundar/.julia/packages/Flux/BPPNj/src/layers/basic.jl:33
The output is slightly noisier, but it tells you which particular method of the function was applied, which module it is from, and exactly where you can find the method definition.