# crossdist

##### Pairwise distances between two different point patterns

Computes the distances between pairs of points taken from two different point patterns.

- Keywords
- spatial

##### Usage

```
crossdist(X, Y, ..., method="C")
crossdist.ppp(X, Y, ..., method="C")
crossdist.default(X, Y, x2, y2, ..., method="C")
```

##### Arguments

- X,Y
- For
`crossdist.ppp`

, the arguments`X`

and`Y`

should be point patterns (objects of class`"ppp"`

). For`crossdist.default`

, the arguments`X`

and`Y`

should be numer - x2,y2
- For
`crossdist.default`

, these should be numeric vectors of equal length specifying the location of the second point pattern. - ...
- Ignored by
`crossdist.ppp`

and`crossdist.default`

. - method
- String specifying which method of calculation to use.
Values are
`"C"`

and`"interpreted"`

.

##### Details

Given two point patterns, this function computes the Euclidean distance from each point in the first pattern to each point in the second pattern, and returns a matrix containing these distances.

The function `crossdist`

is generic, with
a method for point patterns (objects of class `"ppp"`

)
and a default method.

The method for point patterns expects two
point patterns `X`

and `Y`

, and returns the matrix
whose `[i,j]`

entry is the distance from `X[i]`

to
`Y[j]`

.

The default method expects `X`

and `Y`

to be numeric vectors
of equal length specifying the coordinates of the first point pattern.
The arguments `x2`

,`y2`

specify the coordinates of the
second point pattern.
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 faster by a factor of 4.

##### Value

- A matrix whose
`[i,j]`

entry is the distance from the`i`

-th point in the first pattern to the`j`

-th point in the second pattern.

##### See Also

##### Examples

```
data(cells)
d <- crossdist(cells, runifpoint(6))
d <- crossdist(runif(7), runif(7), runif(12), runif(12))
```

*Documentation reproduced from package spatstat, version 1.6-9, License: GPL version 2 or newer*