PrimeMillerRabin

  require 'prime_miller_rabin'
  require 'benchmark'

  primes = load_primes() # Load primes from an external source

  Prime::MillerRabin.speed_intercept
    
  generators = {
    MillerRabin: Prime::MillerRabin.new,
    Generator23: Prime::Generator23.new,
    Eratosthenes: Prime::EratosthenesGenerator.new,
    TrialDivision: Prime::TrialDivisionGenerator.new
  }
    
  padding = ''
  column_width = generators.keys.map(&:size).max
  puts(generators.keys.map { |name| '%-*s' % [column_width, name] }.join('') + '    Number Tested')
    
  time_limit = 120
    
  primes.each_with_index do |number|
    timings = generators.map { |name, generator| [name, Benchmark.measure { Prime.prime?(number, generator) }.total] }.to_h
    puts timings.values.map { |x| '%-*.6f' % [column_width, x] }.push(padding).push(number).join(' ')
    generators = generators.delete_if do |name, _|
      if timings[name] > time_limit
        puts "Removing #{name} as it is now exceeding #{time_limit  / 60} minutes to determine primality."
        padding += ' ' * (column_width + 1)
      end
    end
  end

gem 'prime_miller_rabin'

$ bundle

$ gem install prime_miller_rabin

require 'prime_miller_rabin'

# You now have access to Prime::MillerRabin
Prime.prime?(large_number, Prime::MillerRabin.new)

# Even when using the generator, Ruby's method for #prime? is slower than having Miller Rabin determine it directly.
# Miller Rabin can intercept the Prime.prime? function and call Miller Rabin directly when its generator is used.
# To accomplish this use:
Prime::MillerRabin.speed_intercept

# To use the speed intercept and have Miller Rabin be the default prime generator in all cases use:
Prime::MillerRabin.make_default