# linfun

##### Function on a Linear Network

Create a function on a linear network.

##### Usage

`linfun(f, L)`

##### Arguments

- f
A

`function`

in the R language.- L
A linear network (object of class

`"linnet"`

) on which`f`

is defined.

##### Details

This creates an object of class `"linfun"`

.
This is a simple mechanism for handling a function
defined on a linear network, to make it easier to display
and manipulate.

`f`

should be a `function`

in the R language,
with formal arguments `x,y,seg,tp`

(and optional additional
arguments) where `x,y`

are
Cartesian coordinates of locations on the linear network,
`seg, tp`

are the local coordinates.

The function `f`

should be vectorised: that is,
if `x,y,seg,tp`

are numeric vectors of the same length
`n`

, then `v <- f(x,y,seg,tp)`

should be a vector of length `n`

.

`L`

should be a linear network (object of class `"linnet"`

)
on which the function `f`

is well-defined.

The result is a function `g`

in the R language which belongs to
the special class `"linfun"`

. There are several methods
for this class including `print`

, `plot`

and `as.linim`

.

This function can be called as `g(X)`

where `X`

is an `"lpp"`

object,
or called as `g(x,y)`

or `g(x,y,seg,tp)`

where
`x,y,seg,tp`

are coordinates. If the original function `f`

had additional arguments, then these may be included in the call
to `g`

, and will be passed to `f`

.

##### Value

A function in the R\ language.
It also belongs to the class `"linfun"`

which has methods
for `plot`

, `print`

etc.

##### See Also

`methods.linfun`

for methods applicable to
`"linfun"`

objects.

##### Examples

```
# NOT RUN {
f <- function(x,y,seg,tp) { x+y }
g <- linfun(f, simplenet)
plot(g)
X <- runiflpp(3, simplenet)
g(X)
Z <- as.linim(g)
f <- function(x,y,seg,tp, mul=1) { mul*(x+y) }
g <- linfun(f, simplenet)
plot(g)
plot(g, mul=10)
g(X, mul=10)
Z <- as.linim(g, mul=10)
# }
```

*Documentation reproduced from package spatstat, version 1.63-2, License: GPL (>= 2)*