cpython/Tools/scripts/divmod_threshold.py at 3.15 · python/cpython · GitHub

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#!/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()

cpython/Tools/scripts/divmod_threshold.py at 3.15 · python/cpython · GitHub

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