Non-uniform array data structure

[termi-official]

I would like to quickly address the idea of a new data structure for Ferrite, which is something like OuterNonuniformArray. The purpose would be to have an abstraction to use continuous memory over entities which might need different amounts of data. Concretely this would be introduced for

• per-face data as in BCValues and FaceValues
• DofHandler cell dofs
• L2 projector quadrature point passing
• internal variable storage in examples

The design might be something like

struct OuterNonuniformArray{T, DT <: AbstractArray{T}, OT <: AbstractArray{<:Int}} <: AbstractArray{T}
   data::DT 
   offsets::OT
end

[lijas]

We did have this in the mixed dofhandler for a while:

Ferrite.jl/src/Dofs/MixedDofHandler.jl

Line 51 in 2cd15f7

cell_dofs::CellVector{Int}

(See the definition of CellVector above the MixedDofHandler in the link)

[termi-official]

https://github.com/JuliaArrays/ArraysOfArrays.jl might be an interesting candidate

[KristofferC]

The typical term for this is a "ragged array" I think.