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author | Tim Peters <tim.peters@gmail.com> | 2002-08-15 20:10:45 (GMT) |
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committer | Tim Peters <tim.peters@gmail.com> | 2002-08-15 20:10:45 (GMT) |
commit | e417de0e5697a5242f7530292da13c25eddcf439 (patch) | |
tree | 9ba2552370a1df7624c2d09cf50e1a1827ff7b95 /Objects | |
parent | ab86c2be2415050c71a254ad4e47fb4bdcf3a69f (diff) | |
download | cpython-e417de0e5697a5242f7530292da13c25eddcf439.zip cpython-e417de0e5697a5242f7530292da13c25eddcf439.tar.gz cpython-e417de0e5697a5242f7530292da13c25eddcf439.tar.bz2 |
Illustrating by example one good reason not to trust a proof <wink>.
Diffstat (limited to 'Objects')
-rw-r--r-- | Objects/longobject.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c index 437dd1e..856230e 100644 --- a/Objects/longobject.c +++ b/Objects/longobject.c @@ -1791,9 +1791,9 @@ then we're asking whether asize digits >= f(bsize/2) digits + 2 bits. By #4, asize is at least f(bsize/2)+1 digits, so this in turn reduces to whether 1 digit is enough to hold 2 bits. This is so since SHIFT=15 >= 2. If asize == bsize, then we're asking whether bsize digits is enough to hold -f(bsize/2) digits + 2 bits, or equivalently (by #1) whether c(bsize/2) digits -is enough to hold 2 bits. This is so if bsize >= 1, which holds because -bsize >= KARATSUBA_CUTOFF >= 1. +c(bsize/2) digits + 2 bits, or equivalently (by #1) whether f(bsize/2) digits +is enough to hold 2 bits. This is so if bsize >= 2, which holds because +bsize >= KARATSUBA_CUTOFF >= 2. Note that since there's always enough room for (ah+al)*(bh+bl), and that's clearly >= each of ah*bh and al*bl, there's always enough room to subtract |