pairdist {spatstat} | R Documentation |
Computes the matrix of distances between all pairs of points in a point pattern.
pairdist(X, ..., method="C") pairdist.ppp(X, ..., method="C") pairdist.default(X, Y=NULL, ..., method="C")
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 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 by pairdist.ppp
and pairdist.default .
|
method |
String specifying which method of calculation to use.
Values are "C" and "interpreted" .
Usually not specified.
|
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.
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@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/
data(cells) d <- pairdist(cells) x <- runif(100) y <- runif(100) d <- pairdist(x, y)