JuliaApproximation / JuliaApproximation/ApproxFunBase.jl
Why won't `AbstractMatrix(::SubOperator)` return a `BandedBlockBandedMatrix`?
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Description
I see that the line to return such a matrix is commented out below. Why?
I'd like to preallocate large operator matrices and currently the RaggedMatrix type seems to be the default. The issue is that RaggedMatrix uses too much memory. Currently, I'm just manually using BandedBlockBandedMatrix, but that's not as nice as just being able to use AbstractMatrix(view(SomeOperator, FiniteRange, 1:N))), since I don't want to have to care about the exact memory layout myself.
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Research direction
Start at src/Operators/Operator.jl around line 776 and inspect the commented BandedBlockBandedMatrix return alongside the existing RaggedMatrix path. Trace how AbstractMatrix(view(SomeOperator, FiniteRange, 1:N)) selects its matrix type and determine whether the requested return can avoid excess memory without requiring callers to manage the layout; document the reason or implement the behavior.
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Assessment
- Tech stack
- julia
- Domain
- backend, performance
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100