histogram.rb

histogram.rb

#!/usr/bin/ruby 


binwidth = ARGV[0].to_f
filename = ARGV[1]
rand_file_name = "rand_file-#{(rand*1000000).to_i}.data"

nums = File.open(filename, "r") {|f| f.readlines}.collect {|n| n.to_f }
binned_data = {}
nums.each do |n|
  bin = binwidth * (n/binwidth).to_i + binwidth/2.0
  binned_data[bin] ||= 0
  binned_data[bin] +=  1
end

ff = File.open(rand_file_name, "w")
binned_data.keys.sort.each {|k| ff.puts "#{k}, #{binned_data[k]}"}
ff.close

gnuplot_script = "plot '#{rand_file_name}' u 1:2 w boxes;"
`gnuplot -p -e "#{gnuplot_script}"`