Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

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

This commit is contained in:
Raymond Hettinger 2022-07-24 14:21:29 -05:00 committed by GitHub
parent 0047447294
commit eb9c8a8bea
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
Lib/random.py
View File

@ -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 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 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 _collections_abc import Sequence as _Sequence
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).
# https://dl.acm.org/doi/pdf/10.1145/42372.42381
x = y = 0
c = _log(1.0 - p)
c = _log2(1.0 - p)
if not c:
return x
while True:
y += _floor(_log(random()) / c) + 1
y += _floor(_log2(random()) / c) + 1
if y > n:
return x
x += 1