new_contents: import matplotlib.pyplot as plt
  import numpy as np
  
  from simulate import popgen_simulate
  from simulate_reversible import popgen_simulate_reversible
  
  N_list = [1e2, 5*1e2, 1e3, 5*1e3, 1e4, 5*1e4, 1e5, 5*1e5, 1e6, 5*1e6, 1e7]
  N_list = [1e3, 5*1e3, 1e4, 5*1e4, 1e5, 5*1e5, 1e6, 5*1e6, 1e7]
  # parameters to replicate figure 5a of 2014 valley crossing paper
  # for each param combo, they average over 500 independent runs
  delta = -2e-4
  s = 0.1
  mu_0 = 1e-5
  mu_1 = 1e-4
  mu_1_backward = 1e-4 * 0.5
  mutant_traits_fig5a = [(0.0, mu_0, 0.0),    # base pop
                         (delta, mu_1, 0.0),  # 1-mutant
                         (s, 0.0, 0.0)]       # 2-mutant
  mutant_traits_reversible = [(0.0, mu_0, 0.0),              # base pop
                              (delta, mu_1, mu_1_backward),  # 1-mutant
                              (s, 0.0, 0.0)]                 # 2-mutant
  mutant_traits_reversible_fast = [(0.0, mu_0, 0.0),                      # base pop
                                   (delta, 100*mu_1, 100*mu_1_backward),  # 1-mutant
                                   (s, 0.0, 0.0)]                         # 2-mutantN_list = [1e2, 5*1e2, 1e3, 5*1e3, 1e4, 5*1e4, 1e5, 5*1e5, 1e6, 5*1e6, 1e7]
  
  
  def get_average_run(N, mutant_traits, repeats=1):
      trials = [0 for i in xrange(repeats)]
      for i in xrange(repeats):
          population, t = popgen_simulate_reversible(N, mutant_traits)
          trials[i] = t
      return sum(trials)/float(repeats)
  
  # simulate
  t_list_fig5a = [0 for N in N_list]
  t_list_reversible = [0 for N in N_list]
  t_list_fast = [0 for N in N_list]
  for i, N in enumerate(N_list):
      t_fig5a = get_average_run(N, mutant_traits_fig5a)
      t_list_fig5a[i] = t_fig5a
      t_reversible = get_average_run(N, mutant_traits_reversible)
      t_list_reversible[i] = t_reversible
      t_fast = get_average_run(N, mutant_traits_reversible_fast)
      t_list_fast[i] = t_fast
      
  # plot output
  plt.plot(N_list, t_list_fig5a, '--x', label='default')
  plt.plot(N_list, t_list_reversible, '--o', label='rev')
  plt.plot(N_list, t_list_fast, '--d', label='rev_fast')
  ax = plt.gca()
  ax.set_xscale('log')
  ax.set_yscale('log')
  plt.xlabel('N')
  plt.ylabel('time')
  plt.legend(loc='upper right')
  
  plt.show()
  
subject: include both reversible and nonreversible scripts for now, until time issue resolved