In Python I can have an numpy array a with dimensions (2, 3, 2) and b with (3) and do
c = a[:, :, :] + b[None, :, None]
I did not manage to figure out how to do this with Julia broadcast, because I do not know how to select the middle dimension.
c = broadcast(+, a, b)
What is the proper way to do this?
a .+ b'
For example
julia> a = rand(2,3,2)
2×3×2 Array{Float64, 3}:
[:, :, 1] =
0.690245 0.358837 0.240053
0.206133 0.0406269 0.985161
[:, :, 2] =
0.207407 0.602692 0.483698
0.625693 0.236401 0.306893
julia> b = rand(3)
3-element Vector{Float64}:
0.1824121021951648
0.33153839873473867
0.024984235771881913
julia> a .+ b'
2×3×2 Array{Float64, 3}:
[:, :, 1] =
0.872657 0.690375 0.265037
0.388545 0.372165 1.01015
[:, :, 2] =
0.38982 0.93423 0.508682
0.808105 0.56794 0.331878
To elaborate, vectors in Julia are row vectors by default; transpose to a column vector to broadcast over the second dimension.