Re: st: Combinations of 3

[Tirthankar Chakravarty <tirthankar.chakravarty@gmail.com>]

******************************************
// generate some data
clear
set obs 100
g v = runiform()
forv i=1/6{
	g n`i' = runiform()
}
// sum variables
forv i=1/5 {
	forv j = `=`i'+1'/6 {
		g v_n`i'_n`j' = v + n`i' + n`j'
	}
}
su
******************************************

T
On Sun, Dec 19, 2010 at 4:03 PM, Kari Hexem <khexem@gmail.com> wrote:
> Hi,
>
> I would like to sum the numbers of variable v with 6 other variables:
> n1, n2, n3, n4, n5, n6,
> in combinations of 3.  So the results would be the sums of the
> following variables,
> identified using 15 combinations (6 choose 2), or, to spell it out,
> the sums of each of these
> following possibilities:
> v-n1-n2
> v-n1-n3
> v-n1-n4
> v-n1-n5
> v-n1-n6
> v-n2-n3
> v-n2-n4
> v-n2-n5
> v-n2-n6
> v-n3-n4
> v-n3-n5
> v-n3-n6
> v-n4-n5
> v-n4-n6
> v-n5-n6
>
> I can get the sum of the first two of the 3 variables by using the
> following code:
> forvalues i=1(1)6 {
>  gen sum`i' = v + n`i'
> }
>
> but I can't figure out how to add in the 3d variable, which can't be a
> repeat of the 2nd variable (ie. v-n1-n1 is not allowed).  Thoughts?  I
> feel like it should have something to do with nested loops, or the
> -selectvars- command, but I am totally stuck.  Any help would be
> greatly appreciated.
>
> Thanks,
> Kari
> *
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>



-- 
To every ω-consistent recursive class κ of formulae there correspond
recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
belongs to Flg(κ) (where v is the free variable of r).

*
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