Interpolations.jl
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JuliaMath
Possibly missing documentation for boundary conditions
At http://juliamath.github.io/Interpolations.jl/latest/control/, it is said
The following boundary conditions are implemented: Flat, Line (alternatively, Natural), Free, Periodic and Reflect; their mathematical implications are described in detail in their docstrings.
I'm not sure where these docstrings are that are mentioned. If I try and look at them, I get:
help?> Flat
search: Flat float Float64 Float32 Float16 floatmin floatmax Cfloat BigFloat prevfloat nextfloat maxintfloat RFLUFactorization AbstractFloat findlast
Flat(gt) sets the extrapolation slope to zero
help?> Line
search: Line Lines lines Linear lines! LinearTicks LineElement LinearSolve LineSegments LinearIndices linesegments LinearProblem LinearAlgebra
Line(gt) uses a constant slope for extrapolation
help?> Natural
search: Natural UnivariateMixture
No documentation found.
Summary
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struct Line{GT<:Union{Nothing, Interpolations.GridType}}
Fields
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gt :: GT<:Union{Nothing, Interpolations.GridType}
Supertype Hierarchy
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Line{GT<:Union{Nothing, Interpolations.GridType}} <: Interpolations.BoundaryCondition <: Interpolations.Flag <: Any
help?> Free
search: Free Frechet UndefRefError DifferentialEquations FiniteDifferenceMonotonicInterpolation StochasticDiffEqRODEAdaptiveAlgorithm
No documentation found.
Summary
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struct Free{GT<:Union{Nothing, Interpolations.GridType}}
Fields
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gt :: GT<:Union{Nothing, Interpolations.GridType}
Supertype Hierarchy
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Free{GT<:Union{Nothing, Interpolations.GridType}} <: Interpolations.BoundaryCondition <: Interpolations.Flag <: Any
help?> Periodic
search: Periodic PeriodicCallback MultipleLinearRegressionBounded
Periodic(gt) applies periodic boundary conditions
help?> Reflect
search: Reflect reflect! ProcessFailedException dropped_files
Reflect(gt) applies reflective boundary conditions
Of course, the mathematical implication of the boundary conditions is somewhat clear, but the "in detail" part of the quote above makes me think that maybe this is a mistake and should be more documentation here?
Yes it looks like the doc string is missing: https://github.com/JuliaMath/Interpolations.jl/blob/4c29ad6cf21e426acc4e1e4a2963aaa20ae64d61/src/Interpolations.jl#L97-L108
Are you interested in writing them?
Free:
The free boundary condition makes sure the interpoland has a continuous
third derivative at the second-to-outermost cell boundary
https://cs.github.com/JuliaMath/Interpolations.jl/blob/4c29ad6cf21e426acc4e1e4a2963aaa20ae64d61/doc/Interpolations_algebra.nb#L927