How to use GamesDice to produce stats for fixed size dice pool

games_dice_example.rb

# Related to: http://rpg.stackexchange.com/questions/37270/how-can-i-get-anydice-to-determine-these-odds

require 'games_dice'

die_types = [ 4, 6, 8, 10, 12, 20 ]

die_types.each_cons(2) do |type_lower, type_upper|
  (0..6).each do |num_upper|
    num_lower = 6 - num_upper

    # We want 6d20, but we don't want repetition
    next if num_upper == 6 && type_upper != 20

    # Generate dice description. GamesDice does not treat e.g. "0d6" as valid.
    # The "m4" is a way of coding: Score 0 by default, or 1 when result is 4 or higher
    dice_text = case num_upper
      when 0 then "#{num_lower}d#{type_lower}m4"
      when 6 then "#{num_upper}d#{type_upper}m4"
      else "#{num_lower}d#{type_lower}m4 + #{num_upper}d#{type_upper}m4"
    end

    # Creates a GamesDice::Dice object
    dice_pool = GamesDice.create dice_text

    # Output heading then probabilities
    puts "\n#{dice_text.gsub(/m4/,'')}, target 4+"
    probs = dice_pool.probabilities
    (1..6).each do |successes|
      print "   #{successes}:#{sprintf('%5.1f', probs.p_ge(successes) * 100)}%"
    end
    puts
  end
end

I'm happy to answer questions about this script here, or on StackOverflow.

\Would this be an option for working out Probability of being able to purchase a card in my custom die system?

Question here