Dense layer field alias

Specific Domains Machine Learning
1

Hi, I am writing a custom layer and am trying to emulate the UI of Flux layers.

In the definition of Flux’s Dense layer the Dense struct has a field weight, but this field also has a kind of alias W. How/where is this alias defined? It was not apparent to me from reading the source code.

using Flux
a = Dense(3,3)
a.W === a.weight # is true
2

a.W is actually getproperty(a, :W). This is not specific to Flux, but how the dot works in Julia.

Flux adds a specialization to getproperty. See @which a.W and the corresponding source file.

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3

Thanks :slight_smile:
I found the relevant lines of code in my local install by using @which like you explained. Turns out a.W and a.b is deprecated syntax, and has been removed from master in this commit.

Old field name aliasing code 
function Base.getproperty(a::Dense, s::Symbol)
  if s === :W
    Base.depwarn("field name dense.W is deprecated in favour of dense.weight", :Dense)
    return getfield(a, :weight)
  elseif s === :b
    Base.depwarn("field name dense.b is deprecated in favour of dense.bias", :Dense)
    return getfield(a, :bias)
  end
  return getfield(a, s)
end
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