pairdist.default {spatstat}R Documentation

Pairwise distances

Description

Computes the matrix of distances between all pairs of points in a set of points

Usage

  ## Default S3 method:
  pairdist(X, Y=NULL, ..., method="C")

Arguments

X,Y Arguments specifying the coordinates of a set of points. Typically X and Y would be numeric vectors of equal length. Alternatively Y may be omitted and X may be a list with two components x and y, or a matrix with two columns.
... Ignored.
method String specifying which method of calculation to use. Values are "C" and "interpreted". Usually not specified.

Details

Given the coordinates of a set of points, this function computes the Euclidean distances between all pairs of points, and returns the matrix of distances. It is a method for the generic function pairdist.

The arguments X and Y must determine the coordinates of a set of points. Typically X and Y would be numeric vectors of equal length. Alternatively Y may be omitted and X may be a list with two components named x and y, or a matrix or data frame with two columns.

The argument method is not normally used. It is retained only for checking the validity of the software. If method = "interpreted" then the distances are computed using interpreted R code only. If method="C" (the default) then C code is used. The C code is somewhat faster.

Value

A square matrix whose [i,j] entry is the distance between the points numbered i and j.

Author(s)

Pavel Grabarnik pavel.grabar@issp.serpukhov.su and Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/

See Also

crossdist, nndist, Kest

Examples

   x <- runif(100)
   y <- runif(100)
   d <- pairdist(x, y)
   d <- pairdist(cbind(x,y))

[Package spatstat version 1.8-9 Index]