Re: 15! permutations
- To: mathgroup at smc.vnet.net
- Subject: [mg108679] Re: 15! permutations
- From: Nicola Mingotti <n-no-mingotti at g-spam-mail.com>
- Date: Sat, 27 Mar 2010 05:09:58 -0500 (EST)
- References: <hofgdo$fdg$1@smc.vnet.net> <hoi2kt$qgu$1@smc.vnet.net>
There is a typo, of course it's 10^14 seconds ! bye n. On 2010-03-26 11:35:09 +0100, Nicola Mingotti said: > On 2010-03-25 12:11:52 +0100, bn77 said: > >> Hi, >> >> I'm trying to write a program in mathematica that compares roughly >> (15!)^2 / 2 pairs of permutations of length 15. Can mathematica do this >> in a reasonable time? Any experience of this sort? >> >> TIA, >> bn77 > > The number of permutations is then : > N[((15!)^2)/2] => 8.55006*10^23 > > Supposing you can compare 10^9 objects per second > you would need 10^4 seconds that is 3.171 milion years > according to Wolfram Alpha conversion. > > So, no ! If you really need to cycle through all these objects > it's impossible. Brute force here fails, you need to find a smarter > way to solve it. > > bye > > Nicola.