permutations from vectors out of a matrix
Sorry, wrong button. Below a hopefully more helpful solution... Etienne, I don't see the point in avoiding some 'special' packages. If you are willing to change your mind in this regard, try one of the following solutions that work for me: library(combinat) apply(mat, 2, function(x) unique(permn(x))) # each object in the list contains the permutations from once column of mat: apply(mat, 2, function(x) do.call(rbind, unique(permn(x)))) # all vectors you wanted in one matrix; note that they are in the rows, so you might want to transpose this: do.call(rbind, apply(mat, 2, function(x) do.call(rbind, unique(permn(x))))) Not sure about the size of your original problem, though, it might take a while. If you still want to avoid the (small!) package, you might consider copying the code for permn from combinat to define the function within your file. I guess it works (but didn't check) as it does not seem to require any of the other functions of the package. HTH, Michael
-----Original Message-----
From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org] On Behalf Of Etienne Stockhausen
Sent: Montag, 18. Januar 2010 19:20
To: r-help at r-project.org
Subject: [R] permutations from vectors out of a matrix
Dear R-Users,
I'm relativley new to R and have the following problem. I
need all permutations of the vectors created by the collumns
of a matrix. I will give a small example:
p=3
n=2^p-1
#number of obtainable vectors
mat=matrix(0,p,p)
for(i in 1:p)
{
mat[i:1,i]=1/i
}
mat is now a quadratic matrix and n is the number of the
vectors I try to get when I compute all permutations of the
vectors built by the individual columns. It should work for
all quadratic matrix and I want to avoid using some 'special'
packages.
In the example I need the following vectors at the end:
(1,0,0); (0,1,0); (0,0,1); (0.5,0.5,0); (0.5,0,0.5);
(0,0.5,0.5); (1/3,1/3,1/3).
I hope my intention becomes clear.
I'm looking foward to any ideas and clues that might help me.
Thanks in advance and best regards.
Etienne
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