BroadcastableStructs

BroadcastableStructs.jl provides an easy way to create a struct which can be broadcasted as an argument (BroadcastableStruct) and also as a callable (BroadcastableCallable). BroadcastableCallable supports efficient differentiation with Zygote.jl when combined with ChainCutters.jl.

BroadcastableStruct is an efficient way to treat struct-of-arrays as array-of-structs within broadcasting expressions without actually constructing the array.

julia> using BroadcastableStructs: BroadcastableStruct

julia> struct Point2D{TX, TY} <: BroadcastableStruct
           x::TX
           y::TY
       end

julia> dist(p::Point2D, q::Point2D) = sum(abs(p.x - q.x) + abs(p.y - q.y));

julia> p = Point2D(1:2, 3:4)
Point2D{UnitRange{Int64},UnitRange{Int64}}(1:2, 3:4)

julia> q = Point2D(5, 6)
Point2D{Int64,Int64}(5, 6)

julia> dist.(p, q)
2-element Array{Int64,1}:
 7
 5

BroadcastableCallable can be used to create a callable object that is broadcasted over its parameters as well as arguments.

julia> using BroadcastableStructs: BroadcastableCallable

julia> struct WeightedAdd{A, B} <: BroadcastableCallable
           a::A
           b::B
       end

julia> (f::WeightedAdd)(x, y) = f.a * x + f.b * y;

julia> WeightedAdd(1, 2)(3, 4)
11

julia> f = WeightedAdd(1:2, 3)
WeightedAdd{UnitRange{Int64},Int64}(1:2, 3)

julia> f.(4:5, 6)
2-element Array{Int64,1}:
 22
 28