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spatstat (version 1.52-1)

pairdist.pp3: Pairwise distances in Three Dimensions

Description

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

Usage

# S3 method for pp3
pairdist(X, …, periodic=FALSE, squared=FALSE)

Arguments

X

A point pattern (object of class "pp3").

Ignored.

periodic

Logical. Specifies whether to apply a periodic edge correction.

squared

Logical. If squared=TRUE, the squared distances are returned instead (this computation is faster).

Value

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

Details

This is a method for the generic function pairdist.

Given a three-dimensional point pattern X (an object of class "pp3"), this function computes the Euclidean distances between all pairs of points in X, and returns the matrix of distances.

Alternatively if periodic=TRUE and the window containing X is a box, then the distances will be computed in the `periodic' sense (also known as `torus' distance): opposite faces of the box are regarded as equivalent. This is meaningless if the window is not a box.

If squared=TRUE then the squared Euclidean distances d2 are returned, instead of the Euclidean distances d. The squared distances are faster to calculate, and are sufficient for many purposes (such as finding the nearest neighbour of a point).

See Also

pairdist, crossdist, nndist, K3est

Examples

Run this code
# NOT RUN {
   X <- runifpoint3(20)
   d <- pairdist(X)
   d <- pairdist(X, periodic=TRUE)
   d <- pairdist(X, squared=TRUE)
# }

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