

   SSiimmuullaatteess SSeeqquueennttiiaall SSppaattiiaall IInnhhiibbiittiioonn PPooiinntt PPrroocceessss

        SSI(n, r)

   AArrgguummeennttss::

          n: number of points

          r: inhibition distance

   DDeessccrriippttiioonn::

        Simulates SSI (sequential spatial inhibition) point
        process.

   VVaalluuee::

        list of vectors of `x' and `y' coordinates

   SSiiddee EEffffeeccttss::

        Uses the random number generator.

   WWAARRNNIINNGGSS::

        will never return if `r' is too large and it cannot
        place `n' points

   SSeeee AAllssoo::

        `Psim', `Strauss'

