julia-xarray.org

julia xarray impl notes

links

https://github.com/JuliaArrays/AxisArrays.jl

julia docs

type stuff

https://docs.julialang.org/en/v1/manual/performance-tips/#Types-with-values-as-parameters-1 https://docs.julialang.org/en/v1/manual/types/#Parametric-Types-1 https://docs.julialang.org/en/v1/manual/types/#%22Value-types%22-1 https://docs.julialang.org/en/v1/manual/constructors/

UX

https://docs.julialang.org/en/v1/base/io-network/#Multimedia-I/O-1 https://docs.julialang.org/en/v1/manual/types/#man-custom-pretty-printing-1 https://docs.julialang.org/en/v1/manual/conversion-and-promotion/#Promotion-1 https://docs.julialang.org/en/v1/manual/interfaces/ https://docs.julialang.org/en/v1/manual/metaprogramming/index.html

broadcasting

https://docs.julialang.org/en/v0.6/manual/arrays/#Broadcasting-1 so: need to line up names to broadcast things https://github.com/JuliaLang/julia/blob/master/base/broadcast.jl

discussions

https://discourse.julialang.org/t/custom-indexing-for-a-named-array/20014

possibly useful things

https://github.com/mcabbott/TensorCast.jl https://github.com/ahwillia/Einsum.jl https://github.com/c42f/FastClosures.jl https://github.com/FluxML/Flux.jl

python

http://xarray.pydata.org/en/stable/ https://github.com/harvardnlp/NamedTensor (sorta) http://holoviews.org/

prototype

struct NamedArray{T, N, Names, Arr <: AbstractArray{T, N}} <: AbstractArray{T, N}
    arr :: Arr
    NamedArray(names::Tuple{Vararg{Symbol, N}}, arr :: Arr) where {T,N,Arr <: AbstractArray{T, N}} = begin
        new{T, N, names, Arr}(arr)
    end
end
Base.size(A :: NamedArray) = size(A.arr)
Base.IndexStyle(:: NamedArray) = IndexCartesian()
#@inline Base.getindex(A :: NamedArray{T, N, Names, Arr}, I::Vararg{Int, N}) where {T, N, Names, Arr} =
#    Base.getindex(A.arr, I...)
@inline Base.getindex(A :: NamedArray{T, N, Names, Arr}, I) where {T, N, Names, Arr} =
    Base.getindex(A.arr, I...)
#@inline Base.setindex!(A :: NamedArray{T, N, Names, Arr}, v, I::Vararg{Int, N}) where {T, N, Names, Arr} =
#    Base.setindex!(A.arr, v, I...)
@inline Base.setindex!(A :: NamedArray{T, N, Names, Arr}, v, I) where {T, N, Names, Arr} =
    Base.setindex!(A.arr, v, I...)

test = NamedArray((:time, :index), [1 2; 3 4])

test[1:2, 3:4]

this is neat! extensions:

• non-symbol dimensions to avoid confusion between libraries.
• metadata on dimensions, output name.
• custom dimension grids like holoviews (how does julia implement that?)

Base.size(A :: NamedArray) = size(A.arr)
Base.IndexStyle(:: NamedArray) = IndexCartesian()
Base.getindex(A :: NamedArray{T, N, Names, Arr}, I::Vararg{Int, N}) where {T, N, Names, Arr} =
    Base.getindex(A.arr, I...)

Base.getindex(test, 1:2)

Base.getindex(A :: NamedArray{T, N, Names, Arr}, i::Int) where {
    T, N, Names, Arr,
} = getindex(A.arr, i)