Tests a list of neighboring regions for proper format. Neighborhood is
tested for being symmetrical. Causes an error if tests fail.
Usage
nbtest(nblist, n.regions=length(nblist))
Value
invisible{TRUE}.
Arguments
nblist
A list with a component for
every region. The
components are vectors of integers indicating
neighboring regions. A region without neighbors (e.g., an island)
should be assigned a vector numeric(0).