Combination with repetition

["José Luis Aznarte M."-2]

   Hi there! I can't find any information about creating combinations
with repetitions in R. The function combn() does create combinations,
but _without_ repetitions.
    Here is what I need to do:

svIter <- 1000
xx <- matrix(rnorm(m*n), c(m, n))
sequence <- seq(range(xx)[1], range(xx)[2], length.out = svIter^(1/q))
expand.grid(secuence, secuence, .../q times/..., secuence)

That is, I need a grid which covers a q-dimensional space with range
range(xx) for each dimension, and a total number of points close to
svIter. My problem could be solved by writting the expand.grid call at
runtime, but I think that is not very elegant and, overall, I don't know
how to do that. If combn() accepted repetitions, it'd be solved also.
    Any help will be greatly appreciated.
    Bests,

--                                                      --
Jose Luis Aznarte M.       http://decsai.ugr.es/~jlaznarte
Department of Computer Science and Artificial Intelligence
Universidad de Granada           Tel. +34 - 958 - 24 04 67
GRANADA (Spain)                  Fax: +34 - 958 - 24 00 79

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[Dimitris Rizopoulos]

you could use something like the following:

expand.grid(rep(list(1:3), 4))


I hope it helps.

Best,
Dimitris


Jose Luis Aznarte M. wrote:

>   Hi there! I can't find any information about creating combinations
> with repetitions in R. The function combn() does create combinations,
> but _without_ repetitions.
>    Here is what I need to do:
>
> svIter <- 1000
> xx <- matrix(rnorm(m*n), c(m, n))
> sequence <- seq(range(xx)[1], range(xx)[2], length.out = svIter^(1/q))
> expand.grid(secuence, secuence, .../q times/..., secuence)
>
> That is, I need a grid which covers a q-dimensional space with range
> range(xx) for each dimension, and a total number of points close to
> svIter. My problem could be solved by writting the expand.grid call at
> runtime, but I think that is not very elegant and, overall, I don't know
> how to do that. If combn() accepted repetitions, it'd be solved also.
>    Any help will be greatly appreciated.
>    Bests,
>
> --                                                      --
> Jose Luis Aznarte M.       http://decsai.ugr.es/~jlaznarte
> Department of Computer Science and Artificial Intelligence
> Universidad de Granada           Tel. +34 - 958 - 24 04 67
> GRANADA (Spain)                  Fax: +34 - 958 - 24 00 79
>
> ______________________________________________
> [hidden email] 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.
>
>

--
Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: [phone]
Fax: [phone]
Web: http://perswww.kuleuven.be/dimitris_rizopoulos/



Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

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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.

[cberry]

On Fri, 15 Aug 2008, Jose Luis Aznarte M. wrote:

>  Hi there! I can't find any information about creating combinations with
> repetitions in R. The function combn() does create combinations, but
> _without_ repetitions.
>    Here is what I need to do:
>
> svIter <- 1000
> xx <- matrix(rnorm(m*n), c(m, n))
> sequence <- seq(range(xx)[1], range(xx)[2], length.out = svIter^(1/q))
> expand.grid(secuence, secuence, .../q times/..., secuence)

See

  ?do.call

do.call( expand.grid, rep( list(sequence), q ) )

HTH,

Chuck

p.s. Using function names as object names (e.g. 'q') is considered bad
practice

>
> That is, I need a grid which covers a q-dimensional space with range
> range(xx) for each dimension, and a total number of points close to svIter.
> My problem could be solved by writting the expand.grid call at runtime, but I
> think that is not very elegant and, overall, I don't know how to do that. If
> combn() accepted repetitions, it'd be solved also.
>    Any help will be greatly appreciated.
>    Bests,
>
> --                                                      --
> Jose Luis Aznarte M.       http://decsai.ugr.es/~jlaznarte
> Department of Computer Science and Artificial Intelligence
> Universidad de Granada           Tel. +34 - 958 - 24 04 67
> GRANADA (Spain)                  Fax: +34 - 958 - 24 00 79
>
> ______________________________________________
> [hidden email] 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.
>

Charles C. Berry                            [phone]
                                             Dept of Family/Preventive Medicine
E mailto:[hidden email]            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901

______________________________________________
[hidden email] 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.