MathGroup Archive 2010

[Date Index] [Thread Index] [Author Index]

Search the Archive

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.



  • Prev by Date: Re: Fourier transform of exponential function
  • Next by Date: Re: Fourier transform of exponential function
  • Previous by thread: Re: 15! permutations
  • Next by thread: Re: 15! permutations