| #!/usr/bin/env python3 | |
| # | |
| # Determine threshold for switching from longobject.c divmod to | |
| # _pylong.int_divmod(). | |
| from random import randrange | |
| from time import perf_counter as now | |
| from _pylong import int_divmod as divmod_fast | |
| BITS_PER_DIGIT = 30 | |
| def rand_digits(n): | |
| top = 1 << (n * BITS_PER_DIGIT) | |
| return randrange(top >> 1, top) | |
| def probe_den(nd): | |
| den = rand_digits(nd) | |
| count = 0 | |
| for nn in range(nd, nd + 3000): | |
| num = rand_digits(nn) | |
| t0 = now() | |
| e1, e2 = divmod(num, den) | |
| t1 = now() | |
| f1, f2 = divmod_fast(num, den) | |
| t2 = now() | |
| s1 = t1 - t0 | |
| s2 = t2 - t1 | |
| assert e1 == f1 | |
| assert e2 == f2 | |
| if s2 < s1: | |
| count += 1 | |
| if count >= 3: | |
| print( | |
| "for", | |
| nd, | |
| "denom digits,", | |
| nn - nd, | |
| "extra num digits is enough", | |
| ) | |
| break | |
| else: | |
| count = 0 | |
| else: | |
| print("for", nd, "denom digits, no num seems big enough") | |
| def main(): | |
| for nd in range(30): | |
| nd = (nd + 1) * 100 | |
| probe_den(nd) | |
| if __name__ == '__main__': | |
| main() | |