Pairwise distances
Computes the matrix of distances between all pairs of points in a point pattern.
## S3 method for class 'ppp' pairdist(X, ..., periodic=FALSE, method="C", squared=FALSE)
X |
A point pattern (object of class |
... |
Ignored. |
periodic |
Logical. Specifies whether to apply a periodic edge correction. |
method |
String specifying which method of calculation to use.
Values are |
squared |
Logical. If |
This is a method for the generic function pairdist.
Given a point pattern X (an object of class "ppp"),
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
rectangle, then the distances will be computed in the ‘periodic’
sense (also known as ‘torus’ distance): opposite edges of the
rectangle are regarded as equivalent.
This is meaningless if the window is not a rectangle.
If squared=TRUE then the squared Euclidean distances
d^2 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).
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.
A square matrix whose [i,j] entry is the distance
between the points numbered i and j.
Pavel Grabarnik pavel.grabar@issp.serpukhov.su and Adrian Baddeley Adrian.Baddeley@curtin.edu.au
data(cells) d <- pairdist(cells) d <- pairdist(cells, periodic=TRUE) d <- pairdist(cells, squared=TRUE)
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