JuliaApproximation / JuliaApproximation/FastTransforms.jl
Add oscillatory integral quadratures
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- Dominant language
- Julia
- Stars
- 281
- Forks
- 27
- PR merge metrics
- No merged PRs in 30d
Description
According to R. Piessens and M. Branders, On the computation of Fourier transforms of singular functions, J. Comp. Appl. Math., 43:159-169, 1992, the modified Chebyshev moments of the complex exponential (multiplied by algebraic endpoint singularities) satisfy a many-term recurrence relation that is neither stable in the forward nor backward directions. How to proceed?
Combination of moment-based quadrature with fast orthogonal polynomial transforms to change bases is now irresistible: for example, the modified Legendre moments of the complex exponential are proportional to spherical Bessel functions that satisfy a three-term recurrence relation with well-known stability properties. By changing bases, we would simplify the recurrence and secure the stability by design.
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
No files, tests, or entry points are named in the issue. Start by reading the cited Piessens and Branders paper and the issue’s discussion of modified Chebyshev and Legendre moments. Done would require an agreed, stable design for oscillatory integral quadratures and a concrete implementation scope.
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
- 20/100