The actual calculations are preformed by `density.ppp`

and
`…`

arguments are passed thereto for control over the pixel
resolution etc. (These arguments are then passed on to `pixellate.ppp`

and `as.mask`

.)

For the function method the given kernel function should accept
vectors of x and y coordinates as its first two arguments. Any
additional arguments may be passed through the `…`

.

The function method also accepts the optional parameter `mu`

(defaulting to 1) specifying the mean number of points per cluster (as
a numeric) or the inhomogeneous reference cluster intensity (as an
`"im"`

object or a `function(x,y)`

). The interpretation of
`mu`

is as explained in the simulation functions referenced in
the See Also section below.

For the character method `model`

must be one of:
`model="Thomas"`

for the Thomas process,
`model="MatClust"`

for the Matern cluster process,
`model="Cauchy"`

for the Neyman-Scott cluster process with
Cauchy kernel, or `model="VarGamma"`

for the Neyman-Scott
cluster process with Variance Gamma kernel. For all these models the
parameter `scale`

is required and passed through `…`

as
well as the parameter `nu`

when `model="VarGamma"`

. This
method calls `clusterfield.function`

so the parameter `mu`

may also be passed through `…`

and will be interpreted as
explained above.

The kppm method extracts the relevant information from the fitted
model (including `mu`

) and calls `clusterfield.function`

.