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bug#22567: Factoring 38 nines
From: |
SasQ |
Subject: |
bug#22567: Factoring 38 nines |
Date: |
Fri, 05 Feb 2016 08:47:47 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 |
Hello.
Looks like I found a bug in the `factor` command
(version 8.21 on Gentoo Linux). For the following input:
factor 99999999999999999999999999999999999999
it hangs, but for a longer number:
factor 100000000000000000000000000000000000000
it works fine, factoring it as 38 "2"s and 38 "5"s.
It also works fine for a number one less:
factor 99999999999999999999999999999999999998
factoring it as:
2 7 277294097 25759138835390148450014993081
and it also works for the biggest 64-bit prime:
factor 18446744073709551557
just returning itself.
So the only problematic input is the string of 38 "9"s.
P.S.: I'm curious though: How does it work that it is able to factor
such big numbers in such a short time without large prime tables?
--
SasQ
- bug#22567: Factoring 38 nines,
SasQ <=
- bug#22567: Factoring 38 nines, Eric Blake, 2016/02/05
- bug#22567: Factoring 38 nines, Eric Blake, 2016/02/05
- bug#22567: Factoring 38 nines, SasQ, 2016/02/05
- bug#22567: Factoring 38 nines, Eric Blake, 2016/02/05
- bug#22567: Factoring 38 nines, Jim Meyering, 2016/02/05
- bug#22567: Factoring 38 nines, Linda Walsh, 2016/02/07
- bug#22567: Factoring 38 nines, f0rhum, 2016/02/08
- bug#22567: Factoring 38 nines, Eric Blake, 2016/02/08
- bug#22567: Factoring 38 nines, Leslie S Satenstein, 2016/02/05