1  #!/usr/bin/env python3
       2  #
       3  # Determine threshold for switching from longobject.c divmod to
       4  # _pylong.int_divmod().
       5  
       6  from random import randrange
       7  from time import perf_counter as now
       8  from _pylong import int_divmod as divmod_fast
       9  
      10  BITS_PER_DIGIT = 30
      11  
      12  
      13  def rand_digits(n):
      14      top = 1 << (n * BITS_PER_DIGIT)
      15      return randrange(top >> 1, top)
      16  
      17  
      18  def probe_den(nd):
      19      den = rand_digits(nd)
      20      count = 0
      21      for nn in range(nd, nd + 3000):
      22          num = rand_digits(nn)
      23          t0 = now()
      24          e1, e2 = divmod(num, den)
      25          t1 = now()
      26          f1, f2 = divmod_fast(num, den)
      27          t2 = now()
      28          s1 = t1 - t0
      29          s2 = t2 - t1
      30          assert e1 == f1
      31          assert e2 == f2
      32          if s2 < s1:
      33              count += 1
      34              if count >= 3:
      35                  print(
      36                      "for",
      37                      nd,
      38                      "denom digits,",
      39                      nn - nd,
      40                      "extra num digits is enough",
      41                  )
      42                  break
      43          else:
      44              count = 0
      45      else:
      46          print("for", nd, "denom digits, no num seems big enough")
      47  
      48  
      49  def main():
      50      for nd in range(30):
      51          nd = (nd + 1) * 100
      52          probe_den(nd)
      53  
      54  
      55  if __name__ == '__main__':
      56      main()