#!/usr/bin/ruby -w

=begin
/***************************************************************************
 *   Copyright (C) 2008 by Paul Lutus                                      *
 *   lutusp@arachnoid.com                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
=end

histogram = true
plot = true

# c = cicadas
# p = predators

maxc = 25 # cicada test domain
maxp = 25 # predator test domain
sample_years = 1000
total = Array.new(maxc+1,0)

# cicada reproductive cycle
for c in 1..maxc
   cicadas = 2
   # predator reproductive cycle
   for p in 1..maxp
      for y in 1..sample_years
         # if cicadas and predators appear at once
         if((y % c == 0) && (y % p == 0))
            # predators attack cicadas
            cicadas -= 54
            # no fewer than zero cicadas
            cicadas = (cicadas < 0)?0:cicadas
         end
         cicadas += 1
      end
   end
   total[c] = cicadas / (c+1)
end

if histogram

   # show text histogram
   puts "Year Survivors"
   for i in 1..maxc
      printf("%4d %8d %s\n",i,total[i],'*' * (total[i] / 20))
   end

end

if plot

   # create gnuplot histogram
   gnuplot_data=<<-__EOF__
   set style data histogram
   set style fill solid border -1
   set xlabel "Years in Cycle"
   set ylabel "Survivors"
   set xrange [2:25]
   set yrange [0:1000]
   unset xtics
   set title "Cicada Survival Rate vs. Cycle Years"
   plot '-' using 2 lc rgb '#c0e0ff' notitle with boxes,\
   '-' using 0:($2+30):1  notitle with labels
   <data>
   __EOF__

   s = ""
   for i in 0...maxc
      # dummy data to provide an empty left margin
      v = (i > 2)?total[i]:"?"
      s += "#{i} #{v}\n"
   end
   s += "e\n"
   # insert two copies of the data set for the 2 plots
   gnuplot_data.gsub!(%r{<data>},s + s)
   IO.popen("gnuplot -persist","w") { |p| p.write gnuplot_data }

end