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Code Issues Projects Releases Packages Wiki Activity Actions 11

log2() is faster than log() (#95214)

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Raymond Hettinger 2022-07-24 14:21:29 -05:00 • committed by GitHub
parent 0047447294
commit eb9c8a8bea
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1 changed files with 3 additions and 3 deletions
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6
Lib/random.py
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@ -50,7 +50,7 @@ from warnings import warn as _warn
from math import log as _log, exp as _exp, pi as _pi, e as _e, ceil as _ceil from math import log as _log, exp as _exp, pi as _pi, e as _e, ceil as _ceil
from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin
from math import tau as TWOPI, floor as _floor, isfinite as _isfinite from math import tau as TWOPI, floor as _floor, isfinite as _isfinite
from math import lgamma as _lgamma, fabs as _fabs from math import lgamma as _lgamma, fabs as _fabs, log2 as _log2
from os import urandom as _urandom from os import urandom as _urandom
from _collections_abc import Sequence as _Sequence from _collections_abc import Sequence as _Sequence
from operator import index as _index from operator import index as _index
@ -764,11 +764,11 @@ class Random(_random.Random):
# BG: Geometric method by Devroye with running time of O(np). # BG: Geometric method by Devroye with running time of O(np).
# https://dl.acm.org/doi/pdf/10.1145/42372.42381 # https://dl.acm.org/doi/pdf/10.1145/42372.42381
x = y = 0 x = y = 0
c = _log(1.0 - p) c = _log2(1.0 - p)
if not c: if not c:
return x return x
while True: while True:
y += _floor(_log(random()) / c) + 1 y += _floor(_log2(random()) / c) + 1
if y > n: if y > n:
return x return x
x += 1 x += 1