bio-halflife-calculator.rb

unit = ARGV[2]
if unit == "hours"
  report = 12
  dosing_interval = 24
elsif unit == "days"
  report = 1
  dosing_interval = 1
else
  unit = "days"
  report = 1
  dosing_interval = 1
end
half_life = ARGV[0].to_i * dosing_interval
period = ARGV[1].to_i * dosing_interval
dose = 25

steady_states = {
  3 => 121.18,
  4 => 157.13,
  5 => 193.126,
  6 => 229.145,
  7 => 265.18,
  8 => 301.22,
  9 => 337.27,
  10 => 373.32
}

steady_state = steady_states[half_life / dosing_interval] || 10

remaining_in_system = 0

0.upto(period).each do |p|
  remaining_in_system = remaining_in_system * (0.5**(1.fdiv(half_life)))
  remaining_in_system += dose if (p % dosing_interval).zero?
  if (p % report).zero?
    puts "After #{p} #{unit}, dose in system: #{remaining_in_system} - #{remaining_in_system.fdiv(steady_state) * 100}%"
  end
end