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Re: Select from Tuplet using logical expression

  • To: mathgroup at smc.vnet.net
  • Subject: [mg116864] Re: Select from Tuplet using logical expression
  • From: Heike Gramberg <heike.gramberg at gmail.com>
  • Date: Thu, 3 Mar 2011 05:55:04 -0500 (EST)

What about:

Select[Tuples[Range[0, 15],
  3], (! (#[[1]] === #[[3]] || #[[2]] === #[[3]]) &)]

Heike

On 1 Mar 2011, at 10:20, Lengyel Tamas wrote:

> Hello.
>
> Skip if needed:
> ///I am working on a part combinatorical problem with sets of 3
> differently indexed values (e.g. F_i, F_j, F_k, F denoting frequency
> channels) which are subsets of many values (e.g 16 different frequency
> channels, denoted F_0, F_1 ... F_15).
>
> Now, I need to select triplets from these channels, I used Tuplets. So far
> so good. From these I need those combinations where indexes i!=k and/or
> j!=k, and i=j is allowed (e.g {i,j,k} = {12, 12, 4} is a valid channel
> combination, but {3, 12, 3} is not).///
>
> So basically I need to generate triplets from a range of integer numbers,
> where the first and second elements of these triplets do not match the
> third. I thought Select would help, but I don't know if there exists an
> option to control elements' values in a condition.
>
>> From then on I must use these triplets' elements in a function.
>
> But first I am asking your help in generating thos triplets of numbers.
>
> Thanks.
>
> Tam=E1s Lengyel
>
>


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