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delone

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The goal of delone is to provide fast Delaunay triangulation of planar coordinates (X,Y).

Installation

You can install the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("hypertidy/delone")

Example

This is a basic example which shows usage.

tri is an integer vector of triangle triplets that index the input vectors x and y.

x    <- runif(100)
y    <- runif(100)
library(delone)
tri <- xy_tri(x, y)
plot(x, y)
polygon(cbind(x, y)[rbind(matrix(tri, 3L), NA), ])

<img src="man/figures/README-example-1.png" width="100%" />

This suite shows speed comparisons.

delone is the fastest because CGAL is the fastest freely available library for this.

library(delone)
n <- 10000
xy <- cbind(runif(n), runif(n))
## grid for akima
#grid <- expand.grid(x = seq(0, 1, length = as.integer(sqrt(n))), y = seq(0, 1, length = as.integer(sqrt(n))))

## these choice were
## 1) easy for me to try out
## 2)  pure Delaunay convex hull triangulation on bare points (akima is different, uses triangulation under the hood)
## 3) first published here: https://rpubs.com/cyclemumner/416456
rbenchmark::benchmark(
  ## akima doesn't really belong
  #akima = akima::interpp(xy[,1], xy[,2], z = rep(0, n), xo = grid$x, yo = grid$y),
  deldir = deldir::deldir(xy[,1], xy[,2], suppressMsge = TRUE),
  delone = delone::xy_tri(xy[,1], xy[,2]),
  geometry = geometry::delaunayn(xy, options = "Pp"),
  rgeos = rgeos::gDelaunayTriangulation(sp::SpatialPoints(xy)),
  RTriangle = RTriangle::triangulate(RTriangle::pslg(xy)),
  sf = sf::st_triangulate(sf::st_sfc(sf::st_multipoint(xy))),
  ## spatstat belongs but (was) the slowest (needs update to new spatstat.<family>)
  #spatstat = spatstat::delaunay(spatstat::ppp(xy[,1], xy[,2], window = spatstat::owin(range(xy[,1]), range(xy[,2])))),
  tripack = tripack::tri.mesh(xy[,1], xy[,2]),
  replications = 10,
  order = "relative",
  columns = c('test', 'elapsed', 'relative', 'user.self', 'sys.self')
)
#>        test elapsed relative user.self sys.self
#> 2    delone   0.124    1.000     0.124    0.000
#> 5 RTriangle   0.651    5.250     0.636    0.016
#> 7   tripack   0.756    6.097     0.755    0.000
#> 3  geometry   0.764    6.161     0.727    0.036
#> 6        sf  10.956   88.355    10.927    0.022
#> 4     rgeos  16.277  131.266    16.169    0.100
#> 1    deldir  40.263  324.702    40.118    0.133

(There are commercial versions in other software, and Manifold.net is probably the beefiest and fastest of all.)

Code of Conduct

Please note that the delone project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.