Mercurial > hg
view MANIFEST.in @ 373:67081329d49a
Change the size of the short hash representation
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Change the size of the short hash representation
First note that this number doesn't really matter, as we always check
for ambiguous short hash ids.
Here's the math on collision probability:
>>> import math
>>> def p(f, n): return 1 - (1 / math.exp(n**2/(2*f)))
...
>>> p(2**32, 30000.0)
0.09947179164613551 # with 30000 changesets (BKCVS), we have a 9% chance
>>> p(2**32, 65000.0)
0.38850881217977273 # and with a full import from BK, we'd have a 39% chance
>>> p(2**40, 1e6)
0.36539171908447321 # we'd like to be "safe" for 1M csets, so 40 isn't enough
>>> p(2**48, 1e6)
0.001774780051374103 # But 48 looks good
>>> p(2**48, 1e7)
0.16275260939624481
>>> p(2**48, 5e6)
0.043437281083569146
>>> p(2**48, 2e6)
0.0070802434913129764
>>> p(2**48, 3e6)
0.01586009440574343
manifest hash: 24d9f928a463f46708b0e11fb781d5a241851424
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author | mpm@selenic.com |
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date | Wed, 15 Jun 2005 21:11:40 -0800 |
parents | 06bc1ef248a6 |
children | 20fc66131bc0 |
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include hg recursive-include mercurial *.py include tkmerge include hgweb.cgi include hgeditor rewrite-log convert-repo include tests/* include *.txt include templates/map templates/map-*[a-z] include templates/*.tmpl include doc/* include README