Meyners,Michael,LAUSANNE,AppliedMathematics schrieb:
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-boun...@r-project.org
[mailto:r-help-boun...@r-project.org] On Behalf Of Etienne Stockhausen
Sent: Montag, 18. Januar 2010 19:20
To: r-help@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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Hey Michael,
thanks a lot for your answer. I hope I can manage it now. The problem
with the 'small' package is, that I have to solve the task without using
any package as a 'black box'. Therefore I need to get the permutations
on my own.
Best regards and thanks again
Etienne
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
