Much better way to divide work than the way I initially did in port_scanner.py

a_how_to_properly_divide_work.py

# This is probably the right way to divide work.
# At least I think it's better than they I had done it previously in port_scanner.py,
# and I'll fix port_scanner.py to use the below method.
# Kudos to this question and answer for the better way to get intersecting points in 
# a range for an arbitrary number of sections:
# https://stackoverflow.com/questions/20925175/evenly-distribute-x-values-within-a-given-range#20925282
# I played around a while with that and combined it to the way I distributed work in my Elixir port scanner to eventually
# arrive at the below solution.

def child(host, low, high):
  for i in xrange(low, high+1):
    print "scanning %d on %s" % (i, host)

def scan(host, min, max, num_threads):
  if num_threads > max - min + 1:s
    return "Thread count must not be greater than number of ports to scan."
  high = min - 1
  for i in xrange(num_threads):
    low = high + 1
    high = min + (i+1)*(max-min) / num_threads
    print "Thread #%d should scan from %d to %d" % (i+1, low, high)
    child(host, low, high)

# scan("127.0.0.1", 3, 117, 21)

work_demo.exs

# For comparison, I found the work distribution algorithm I arrived at in functional programming to be much simpler
# When I did the imperative version many years ago, it was buggy, and I had to create extra conditions for edge cases.
# When I started working on a functional implementation, I arrived quickly and simply at a solution that had no bugs or
# missing edge cases, and I hadn't had to search the internet for how to do such a task in functional programming - I was
# more or less guided down that path by the paradigm itself.
# Afterward, I finally got around to searching the internet for the proper solution in the imperitive way and put together
# the above implementation (see above comments).

defmodule WorkDemo do

  defp child(host, bottom_port..top_port, open_ports) when bottom_port <= top_port do
    IO.puts "Scanning #{bottom_port} on #{host}"
    # If port is open, add to _open_ports accumulator
    child(host, (bottom_port + 1)..top_port, open_ports)
  end

  defp child(_, _, _open_ports) do
    #IO.puts "Open ports:"
    #IO.inspect open_ports
  end
  
  def scan(host, bot..top, num_processes) when bot <= top do
    mytop = bot + (Enum.count(bot..top) / num_processes |> round) - 1
    IO.puts "Thread ##{num_processes} should scan #{bot} through #{mytop}"
    child(host, bot..mytop, [])
    scan(host, (mytop + 1)..top, num_processes - 1)
  end

  def scan(_, _, 0) do
    IO.puts "Scan complete."
  end
end
# WorkDemo.scan("127.0.0.1", 3..117, 21)