R help - Sep 2006 - Dividing objects in classes using function sample()

Hello everyone,

I've a problem and dont know how to solve. This is my first posting and it
would be fantastic if you could help me.

I want to divide n objects in k classes and need an output with all (n+1)(n+2)/2
possibilities.

For example n=4, k=3:

That would be:
   
   4 0 0
   3 1 0
   3 0 1
   2 2 0
   2 1 1
   2 0 2
   1 3 0 
   1 2 1
   1 1 2
   1 0 3 
   0 3 1 
   0 2 2
   0 1 3
   0 0 4


I tried to you use permn() or sample() but I don't know how to solve.

Please help me!

Best regards,

Maja


-- 


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If n and k are small try brute force.

g <- expand.grid(0:4, 0:4, 0:4)
g[rowSums(g) == 4,]

or more generally:

n <- 4; k <- 3
g <- do.call(expand.grid, rep(list(0:n), k))
g[rowSums(g) == n,]

On 9/2/06, "Maja Schr?ter" <maja.schroeter at gmx.de>
wrote:
> Hello everyone,
>
> I've a problem and dont know how to solve. This is my first posting and
it would be fantastic if you could help me.
>
> I want to divide n objects in k classes and need an output with all
(n+1)(n+2)/2 possibilities.
>
> For example n=4, k=3:
>
> That would be:
>
>   4 0 0
>   3 1 0
>   3 0 1
>   2 2 0
>   2 1 1
>   2 0 2
>   1 3 0
>   1 2 1
>   1 1 2
>   1 0 3
>   0 3 1
>   0 2 2
>   0 1 3
>   0 0 4
>
>
> I tried to you use permn() or sample() but I don't know how to solve.
>
> Please help me!
>
> Best regards,
>
> Maja
>
>
> --
>
>
> "Feel free" ? 10 GB Mailbox, 100 FreeSMS/Monat ...
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

> I want to divide n objects in k classes and need an output with all
> (n+1)(n+2)/2 possibilities.
That's the "set of compositions". You may use the partitions
package and
proceed from there (provided the brute-force method suggested by Gabor
is not viable').

> I want to divide n objects in k classes and need an output with all
> (n+1)(n+2)/2 possibilities.
That's the "set of compositions". You may use the partitions
package and
proceed from there (provided the brute-force method suggested by Gabor
is not viable').