JuliaArrays / JuliaArrays/BlockArrays.jl

Should `BlockArray(arr::AbstractArray{T,N},..)` always create a `BlockArray{T,N,Array{T}}`?

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Julia
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Description

At the moment BlockArray(arr::AbstractArray{T,N},..) creates a BlockArray{T,N,typeof(arr)}. However, for many types subarrays are not of the same type (e.g., Diagonal). I think it is safer to always convert to Array.

The one argument I can see is that it might be nice for BlockArray(::SparseVector) to automatically use sparse data storage.

Another option is to look into whether the type of sub-blocks can be inferred automatically.

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Research direction

Start at the BlockArray(arr::AbstractArray{T,N},..) constructor named in the issue and inspect how Diagonal and SparseVector subarrays are represented. Compare the proposed Array conversion with inferred sub-block types; done requires choosing and implementing one consistent storage policy, with behavior for both examples decided.

Written by the indexing model from the issue text.

Assessment

Tech stack
julia
Domain
data
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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