Simple AI (Neural network) program by Ruby.

Neural network is an algorithm of AI (Artificial intelligence).

I wrote a symple Neural network program by Ruby.

This program judge if the total price of three candies are under the limit.

class Unit
  def initialize(count=3)
    @cells = []
    (count + 1).times { @cells << rand(9) }
  end

  def learn(patterns)
    while !ok ||= false
      ok = true
      result = []
      patterns.values.each do |pattern|
        ans = answer(pattern)
        chk = patterns.check(pattern)
        if ans == chk
          result << 'OK'
        elsif ans && !chk
          result << 'NG'
          ok = false
          penalize(pattern, -1)
        elsif !ans && chk
          result << 'NG'
          ok = false
          penalize(pattern, 1)
        end
      end
      yield(ok, result, @cells)
    end
  end

  def answer(pattern)
    sum = 0
    @cells.length.times { |i| sum += @cells[i + 1] if pattern[i] == 1 }
    @cells[0] <= sum
  end

  def penalize(pattern, direction)
    @cells[0] -= direction
    @cells.length.times { |i| @cells[i + 1] += direction if pattern[i] == 1 }
  end
end

class Patterns
  def initialize
    @limit = 500
    @prices = [310,220,70]
    @values =  [[0, 0, 0],
                [0, 0, 1],
                [0, 1, 0],
                [0, 1, 1],
                [1, 0, 0],
                [1, 0, 1],
                [1, 1, 0],
                [1, 1, 1]]
  end

  attr_reader :values

  def check(pattern)
    sum = 0
    pattern.length.times { |i| sum += @prices[i] * pattern[i] }
    sum <= @limit
  end
end

#--------------------------------
unit = Unit.new
pat = Patterns.new
unit.learn(pat) do |ok, result, cells|
  p result
  break if gets =~ /x/
end