[R] permutations from vectors out of a matrix

[Meyners, Michael, LAUSANNE, AppliedMathematics]

Well, seems it's an assignment, so you should REALLY get them on your
own and not enquire the list. Foolish me...
M.

> -----Original Message-----
> From: einohr2002 at web.de [mailto:einohr2002 at web.de] 
> Sent: Mittwoch, 20. Januar 2010 19:32
> To: Meyners,Michael,LAUSANNE,AppliedMathematics; r-help at r-project.org
> Subject: Re: [R] permutations from vectors out of a matrix
> 
> 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-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
> >>
> >> ______________________________________________
> >> R-help at 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.
> >>     
> >> 
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> >> 01/19/10 08:34:00
> >>
> >>     
> 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
>