JuliaApproximation / JuliaApproximation/ApproxFunBase.jl

What would be the best way to implement support differentiation of a SubSpace

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Dominant language
Julia
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13
Forks
13
Avg merge
10h 33m
Merged PRs (30d)
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Description

At this moment

julia> S = ApproxFunBase.SubSpace(Fourier(), 1:10);

julia> Derivative(S)
DerivativeWrapper : Fourier(【0.0,6.283185307179586❫)|1:10 → SinSpace(【0.0,6.283185307179586❫)⊕CosSpace(【0.0,6.283185307179586❫)
 0.0  0.0  -1.0  0.0   0.0  0.0   0.0  0.0   0.0  0.0
 0.0  0.0   0.0  0.0   0.0  0.0   0.0  0.0   0.0  0.0
 0.0  0.0   0.0  0.0  -2.0  0.0   0.0  0.0   0.0  0.0
 0.0  1.0   0.0  0.0   0.0  0.0   0.0  0.0   0.0  0.0
 0.0  0.0   0.0  0.0   0.0  0.0  -3.0  0.0   0.0  0.0
 0.0  0.0   0.0  2.0   0.0  0.0   0.0  0.0   0.0  0.0
 0.0  0.0   0.0  0.0   0.0  0.0   0.0  0.0  -4.0  0.0
 0.0  0.0   0.0  0.0   0.0  3.0   0.0  0.0   0.0  0.0
 0.0  0.0   0.0  0.0   0.0  0.0   0.0  0.0   0.0  0.0
 0.0  0.0   0.0  0.0   0.0  0.0   0.0  4.0   0.0  0.0

while the first dimension could be finite.

Where would be the best place to interrupt the ApproxFunBase flow to create an Operator that is finite in both dimensions?

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  3. Fork the repository and make your change on a branch.
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Research direction

Start by reproducing the Derivative(S) example and tracing the ApproxFunBase flow into the resulting Operator. Identify where the finite first dimension is lost and determine the appropriate entry point for an operator finite in both dimensions. The work is done when differentiation of this SubSpace produces the intended finite operator.

Written by the indexing model from the issue text.

Assessment

Tech stack
julia
Domain
backend
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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