Cubature over Polygonal Domains.
polyCub
The R package polyCub implements cubature (numerical integration) over polygonal domains. It solves the problem of integrating a continuously differentiable function f(x,y) over simple closed polygons.
For the special case of a rectangular domain along the axes, the cubature package is more appropriate (cf. CRAN Task View: Numerical Mathematics
).
Installation
You can install polyCub from CRAN via:
install.packages("polyCub")
To install the development version from the GitHub repository, use:
## install.packages("remotes")
remotes::install_github("bastistician/polyCub")
Usage
The basic usage is:
library("polyCub")
polyCub(polyregion, f)
polyregion
represents the integration domain as an object of class"owin"
(from spatstat.geom),"gpc.poly"
(from gpclib),"SpatialPolygons"
(from sp), or"(MULTI)POLYGON"
(from sf), or even as a plain list of lists of vertex coordinates ("xylist"
).f
is the integrand and needs to take a two-column coordinate matrix as its first argument.
The polyCub()
function wraps the implemented cubature methods and by default calls polyCub.SV()
, a C-implementation of product Gauss cubature. Directly calling the desired cubature function is preferable, see the list below.
Implemented cubature methods
polyCub.SV()
: General-purpose product Gauss cubature (Sommariva and Vianello, 2007, BIT Numerical Mathematics, https://doi.org/10.1007/s10543-007-0131-2)polyCub.midpoint()
: Simple two-dimensional midpoint rule based on spatstat.geom::as.im.function()
polyCub.iso()
: Adaptive cubature for radially symmetric functions via lineintegrate()
along the polygon boundary (Meyer and Held, 2014, The Annals of Applied Statistics, https://doi.org/10.1214/14-AOAS743, Supplement B, Section 2.4)
For details and illustrations see the vignette("polyCub")
in the installed package or on CRAN.
Applications
The polyCub package evolved from the need to integrate so-called spatial interaction functions (Gaussian or power-law kernels) over the observation region of a spatio-temporal point process. Such epidemic models are implemented in surveillance.
Feedback
Contributions are welcome! Please submit suggestions or report bugs at https://github.com/bastistician/polyCub/issues or via e-mail to maintainer("polyCub")
.
License
The polyCub package is free and open source software, licensed under the GPLv2.