BUBBLES 1.1


    SYNOPSIS

       bubbles: a program for generating random clustered 2d/3d point datasets

    SYNTAX

       bubbles [-u|-n] [-c|-r|-v] [-2d|-3d] npoints nbubbles boxsize

    where:

       -u   (default)  use uniform distribution
       -n	       use an approximation of normal distribution

       -c   (default)  Constant number of sites for bubble.
       -r	       Random number of sites for bubble.
       -v	       Number of sites proprortional to bubble volume.

       -2d	       Sites in two dimensions.
       -3d  (default)  Sites in three dimensions.

       npoints	       total number of sites produced
       nbubbles        number of bubbles (clusters) of sites
       boxsize	       size of box containing all sites

    AUTHOR

       Paolo Cignoni

    NOTES

       This program generate on stdout a wide variety of 3d point (sites)
       random datasets.
       Its main role is building datasets for testing algoritms. For this
       reason user can choose the distribution function between a uniform
       and an approximated normal (the well known gaussian bell). Sites in
       dataset can be clustered in bubbles to simulate strange distribution
       of real data; user can choose the number of bubbles and how many sites
       are contained in each ball. Using Normal distribution each bubble has
       its normal distribution centered in bubble center.

       Switches on site number for bubble:

       -c	       Each bubble contain the same number of sites, more
		       precisely Each bubble contain npoints/nbubbles sites.

       -r	       Each bubble contain a random number of sites, but the
		       sum of all bubbles contains always npoints sites.
		       The random function is the uniform one

       -v	       Each bubble contain a number of sites proportional
		       to its volume. In this way all the bubbles has the
		       same sites density, and the datasets is similar to
		       a unique bubble with some holes (Swiss cheese dataset)

       If there is only one bubble it is origin centered and has the radius
       of the box (it hasn't sense to move and squeeze it).