closepaircounts(X, r)crosspaircounts(X, Y, r)
closepairs(X, rmax, ...)
## S3 method for class 'ppp':
closepairs(X, rmax, ordered=TRUE,
what=c("all","indices","ijd"), ...)
crosspairs(X, Y, rmax, ...)
## S3 method for class 'ppp':
crosspairs(X, Y, rmax, what=c("all", "indices", "ijd"), ...)
"ppp"
).ordered=TRUE
, each pair will appear twice
in the output, as (i,j)
and again as (j,i)
. If
ordered=FALSE
what="all"
(the default) then the
returned information includes the indices i,j
of each pair,
their x,y
coordinates, and the disclosepaircounts
and crosspaircounts
, an integer
vector of length equal to the number of points in X
. For closepairs
and crosspairs
,
a list with components i
and j
,
and possibly other components as described under Details.
rmax
. Floating-point numbers in a computer
are not mathematical Real Numbers: they are approximations using
finite-precision binary arithmetic.
The approximation is accurate to a tolerance of about
.Machine$double.eps
.
If the true interpoint distance $d$ and the threshold rmax
are equal, or if their difference is no more than .Machine$double.eps
,
the result may be incorrect.
closepaircounts(X,r)
counts the number of neighbours for
each point in the pattern X
. That is, for each point
X[i]
, it counts the number of other points X[j]
with j != i
such that d(X[i],X[j]) <= r<="" code=""> where
d
denotes Euclidean distance. The result is an integer vector
v
such that v[i]
is the number of neighbours of
X[i]
.=>
crosspaircounts(X,Y,r)
counts, for each point
in the pattern X
, the number of neighbours in the pattern
Y
. That is, for each point
X[i]
, it counts the number of points Y[j]
such that d(X[i],X[j]) <= r<="" code="">. The result is an integer vector
v
such that v[i]
is the number of neighbours of
X[i]
in the pattern Y
.=>
closepairs(X,rmax)
identifies all pairs of neighbours
in the pattern X
and returns them. The result is
a list with the following components:
[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
If what="indices"
then only the components i
and
j
are returned. This is slightly faster and more efficient
with use of memory.
crosspairs(X,rmax)
identifies all pairs of neighbours
(X[i], Y[j])
between the patterns X
and Y
,
and returns them. The result is
a list with the same format as for closepairs
.
closepairs.pp3
for the corresponding
functions for 3D point patterns.
Kest
, Kcross
,
nndist
, nncross
,
applynbd
, markstat
for functions which use these capabilities.a <- closepaircounts(cells, 0.1)
sum(a)
Y <- split(amacrine)
b <- crosspaircounts(Y$on, Y$off, 0.1)
d <- closepairs(cells, 0.1)
e <- crosspairs(Y$on, Y$off, 0.1)
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