spatstat (version 1.6-5)

pairdist: Pairwise distances

Description

Computes the matrix of distances between all pairs of points in a point pattern.

Usage

pairdist(X, ..., method="C")
  pairdist.ppp(X, ..., method="C")
  pairdist.default(X, Y=NULL, ..., method="C")

Arguments

X,Y

Arguments specifying the locations of a set of points. For pairdist.ppp, the argument X should be a point pattern (object of class "ppp"). For pairdist.default, typically X and <

...

Ignored by pairdist.ppp and pairdist.default.

method

String specifying which method of calculation to use. Values are "C" and "interpreted". Usually not specified.

Value

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

Details

This function computes the Euclidean distances between all pairs of points, and returns the matrix of distances.

The function pairdist is generic, with a method for point patterns (objects of class "ppp") and a default method.

The method for point patterns expects a single point pattern argument X and returns the matrix of its pairwise distances.

The default method expects that X and Y will 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.

See Also

crossdist, nndist, Kest

Examples

data(cells)
   d <- pairdist(cells)

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