LargeSparseArrays.jl

module LargeSparseArrays

import Base: size, getindex, setindex!
export LargeSparseArray

struct LargeSparseArray{T,N} <: AbstractArray{T,N}
    d::Dict{CartesianIndex{N},T}
    dims::NTuple{N,AbstractUnitRange{Int}}
    function LargeSparseArray{T}(dims::Int...) where T
        dim_ranges = Base.OneTo.(dims)
        dict = Dict{CartesianIndex{length(dims)},T}()
        new{T,length(dims)}(dict, dim_ranges)
    end
end
size(s::LargeSparseArray) = length.(s.dims)
getindex(s::LargeSparseArray{T,N}, I::Vararg{Int,N}) where {T,N} =
    all( (I...,) .∈ s.dims ) ? get(s.d, CartesianIndex(I...), zero(T)) : BoundsError(s, (I...,))
setindex!(s::LargeSparseArray{T,N}, v, I::Vararg{Int,N}) where {T,N} =
    s.d[ CartesianIndex(I...) ] = v

end