# pairdist.lpp

##### Pairwise shortest-path distances between points on a linear network

Given a pattern of points on a linear network, compute the matrix of distances between all pairs of points, measuring distance by the shortest path in the network.

- Keywords
- spatial

##### Usage

```
# S3 method for lpp
pairdist(X, ..., method="C")
```

##### Arguments

- X
Point pattern on linear network (object of class

`"lpp"`

).- method
Optional string determining the method of calculation. Either

`"interpreted"`

or`"C"`

.- …
Ignored.

##### Details

Given a pattern of points on a linear network, this function computes the matrix of distances between all pairs of points, measuring distance by the shortest path in the network.

If two points cannot be joined by a path,
the distance between them is infinite (`Inf`

).

The argument `method`

is not normally used. It is
retained only for developers to check the validity of the software.

##### Value

A symmetric matrix, whose values are nonnegative numbers or infinity
(`Inf`

).

##### Algorithms and accuracy

Distances are accurate within the numerical tolerance of the
network, `summary(X)$toler`

.

For network data stored in the non-sparse
representation described in `linnet`

,
then pairwise distances are computed using the matrix of path distances
between vertices of the network, using R code if
`method = "interpreted"`

, or using C code if
`method="C"`

(the default).

For networks stored in the sparse representation,
the argument `method`

has no effect, and the distances are
computed using an efficient C algorithm.

##### See Also

##### Examples

```
# NOT RUN {
X <- runiflpp(12, simplenet)
d <- pairdist(X)
d[1:3, 1:3]
# }
```

*Documentation reproduced from package spatstat, version 1.64-1, License: GPL (>= 2)*