Selfish Mining Sim

sm_sim.rb

#!/usr/bin/env ruby

i = 0
iterations = 1000

sm_hash_pct = 33

public_chain = []
hm_fork = []
sm_fork = []

while i < iterations do
  print "Iteration #{i}: "
  i = i + 1
  
  solution = rand(0..99)
  print "[#{solution}] "
  
  if solution < sm_hash_pct 
    print "SM solved"
    sm_fork.push 'S'
  else
    print "HM solved"
    hm_fork.push 'H'
  end

  if hm_fork.count > sm_fork.count
    #hm is ahead so SM rebase
    public_chain = hm_fork.clone
    sm_fork = hm_fork.clone
  end
  
  if sm_fork.count > hm_fork.count 
    #sm is ahead so the game is on 
    print " - SM #{sm_fork.count - hm_fork.count} ahead"
    if sm_fork.count > public_chain.count + 1
      #if 2+ blocks ahead of main chain then we have a chance to orphan
      if sm_fork.count == hm_fork.count+1 #only 1 block ahead of HM so publish
        print ', HM only 1 behind - publishing...'
        public_chain = sm_fork.clone
        hm_fork = sm_fork.clone
      else
      end
    else
      print ", withholding..."
    end
  end
  
  puts 
  puts "PUB:" + public_chain.join
#   puts "HM :" + hm_fork.join
#   puts "SM :" + sm_fork.join
  
#   STDIN.getc                                                                                                              
  
end

if sm_fork.count > hm_fork.count
  public_chain = sm_fork
else
  public_chain = hm_fork
end


puts "SM expected blocks = #{iterations * sm_hash_pct / 100} actual blocks = #{public_chain.join.count('S')}"
puts "HM expected blocks = #{iterations * (100-sm_hash_pct) / 100} actual blocks = #{public_chain.join.count('H')}"
puts "Orphans: #{orphans = (iterations - public_chain.count)}, rate #{"%.1f" % (100.0 * orphans/public_chain.count)}% "