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