RadialBasisFunctions.jl

Radial Basis Functions in Julia
Author kylebeggs
Popularity
3 Stars
Updated Last
4 Months Ago
Started In
April 2023

RadialBasisFunctions.jl

Build Status Stable Dev License File DOI

This package intends to provide tools for all things regarding Radial Basis Functions (RBF).

Feature Status
Interpolation
Regridding
Partial derivative ($\partial f$)
Laplacian ($\nabla^2 f$, $\Delta f$)
Gradient ($\nabla f$)
Directional Derivative ($\nabla f \cdot v$)
Custom / user supplied ($\mathcal{L} f$)
divergence ($\textrm{div} \mathbf{F}$ or $\nabla \cdot \mathbf{F}$)
curl ($\nabla \times \mathbf{F}$)
Reduced Order Models (i.e. POD)

Currently, we support the following types of RBFs (all have polynomial augmentation by default, but is optional)

Type Function, $\phi(r)$
Polyharmonic Spline $r^n$ where $n=1,3,5, \text{ or } 7$
Inverse Multiquadric $1 / \sqrt{(r \varepsilon)^2+1}$
Gaussian $e^{-(r \varepsilon)^2}$

where $r = \lvert \mathbf{x}-\mathbf{x}_{c} \rvert$ is the Euclidean distance between two points and $\varepsilon$ is a user-supplied shape parameter.

Installation

Simply install the latest stable release using Julia's package manager:

] add RadialBasisFunctions

Current Limitations

  1. A critical dependency of this package is NearestNeighbors.jl which requires that the dimension of each data point is inferrable. To quote from NearestNeighbors.jl:

    The data, i.e., the points to build up the tree from. It can either be

    • a matrix of size nd × np with the points to insert in the tree where nd is the dimensionality of the points and np is the number of points
    • a vector of vectors with fixed dimensionality, nd, which must be part of the type. Specifically, data should be a Vector{V}, where V is itself a subtype of an AbstractVector and such that eltype(V) and length(V) are defined. (For example, with 3D points, V = SVector{3, Float64} works because eltype(V) = Float64 and length(V) = 3 are defined in V.)

    That said, we currently only support the second option here (Vector{AbstractVector}), but plan to support matrix inputs in the future.

  2. Interpolator uses all points, but there are plans to support local collocation / subdomains like the operators use.

Used By Packages

No packages found.