# crossdist.default

##### Pairwise distances between two different sets of points

Computes the distances between each pair of points taken from two different sets of points.

##### Usage

```
# S3 method for default
crossdist(X, Y, x2, y2, …,
period=NULL, method="C", squared=FALSE)
```

##### Arguments

- X,Y
Numeric vectors of equal length specifying the coordinates of the first set of points.

- x2,y2
Numeric vectors of equal length specifying the coordinates of the second set of points.

- …
Ignored.

- period
Optional. Dimensions for periodic edge correction.

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

`"C"`

and`"interpreted"`

.- squared
Logical. If

`squared=TRUE`

, the squared distances are returned instead (this computation is faster).

##### Details

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

This is a method for the generic function `crossdist`

.

This function expects `X`

and `Y`

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

,`y2`

specify the coordinates of the
second set of points.

Alternatively if `period`

is given,
then the distances will be computed in the `periodic'
sense (also known as `torus' distance).
The points will be treated as if they are in a rectangle
of width `period[1]`

and height `period[2]`

.
Opposite edges of the rectangle are regarded as equivalent.

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 set of points
to the `j`

-th point in the second set of points.

##### See Also

`crossdist`

,
`crossdist.ppp`

,
`crossdist.psp`

,
`pairdist`

,
`nndist`

,
`Gest`

##### Examples

```
# NOT RUN {
d <- crossdist(runif(7), runif(7), runif(12), runif(12))
d <- crossdist(runif(7), runif(7), runif(12), runif(12), period=c(1,1))
# }
```

*Documentation reproduced from package spatstat, version 1.57-1, License: GPL (>= 2)*