Recursive, on-demand yielding, lazy parameter sweep generator

combinator.rb

 class Combinator

  include Enumerable
 
  def initialize parameters
    @parameters = parameters
  end
 
  def generate_combinations(index, opts, &block)
    if index == @parameters.length
      block.call opts.clone
      return
    end
    # recurse
    key = @parameters.keys[index]
    @parameters[key].each do |value|
      opts[key] = value
      generate_combinations(index + 1, opts, &block)
    end
  end

  def each &block
    generate_combinations(0, {}, &block)
  end
 
end

parameters = {
  :K=>[21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53,
        55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81], 
  :M=>[0, 1, 2, 3],
  :d=>[0, 1, 2, 3, 4, 5, 6],
  :D=>[0, 1, 2, 3, 4, 5, 6],
  :G=>[50, 75, 100, 125, 150, 175, 200, 225, 250],
  :L=>[50, 100, 150, 200, 250],
  :e=>[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],
  :t=>[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
}
c = Combinator.new parameters

d = c.to_enum

600_000.times do
  a = d.next
end

see also https://gist.github.com/cboursnell/011edf5c2aed2c65dba9