R help - Apr 2009 - n-dimensional vector operations

Let's start with a concrete case of n=3 dimensions.

Along dimension x, I have a matrix of 5 vectors (each with ten rows)
Along dimension y, I have a matrix of 3 vectors (each with ten rows)
Along dimension z, I have a matrix of 2 vectors (each with ten rows)

I am trying to write a:

function(..., funcp) { } 

where funcp(...) is an operator which works on n vectors and returns a
numeric.  For example, averages n=3 columns (one from each dimension) and
takes the standard-deviation of the resultant vector.

So answer should be a matrix of dimension( 5, 3, 2 ) of numeric, in this
case.  At position (4, 2, 1) we would find the numeric answer to funcp(
x[,4],y[,2],z[,1] ).

------------------------------------------------------------
set.seed( 1 );
x <- matrix( runif( 50 ), nrow=10);
y <- matrix( runif( 30 ), nrow=10);
z <- matrix( runif( 20 ), nrow=10);

foo <- function(...,funcp)
{
  matrices <- list(...);
  n.matrices <- length( matrices );
  # What should I put here?!?! -------------------------------------
}



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Tena koe Ken

I may be misunderstanding you, but it seems to me you have a four
dimensional array.  If so:

ken <- array(rnorm(5*3*2*10), dim=c(5,3,2,10))
ken[,1,1,]
ken[1,,1,]

may be sufficient to get you going.

HTH ....

Peter Alspach 
> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Ken-JP
> Sent: Tuesday, 21 April 2009 12:58 p.m.
> To: r-help at r-project.org
> Subject: [R] n-dimensional vector operations
> 
> 
> 
> Let's start with a concrete case of n=3 dimensions.
> 
> Along dimension x, I have a matrix of 5 vectors (each with 
> ten rows) Along dimension y, I have a matrix of 3 vectors 
> (each with ten rows) Along dimension z, I have a matrix of 2 
> vectors (each with ten rows)
> 
> I am trying to write a:
> 
> function(..., funcp) { } 
> 
> where funcp(...) is an operator which works on n vectors and 
> returns a numeric.  For example, averages n=3 columns (one 
> from each dimension) and takes the standard-deviation of the 
> resultant vector.
> 
> So answer should be a matrix of dimension( 5, 3, 2 ) of 
> numeric, in this case.  At position (4, 2, 1) we would find 
> the numeric answer to funcp( x[,4],y[,2],z[,1] ).
> 
> ------------------------------------------------------------
> set.seed( 1 );
> x <- matrix( runif( 50 ), nrow=10);
> y <- matrix( runif( 30 ), nrow=10);
> z <- matrix( runif( 20 ), nrow=10);
> 
> foo <- function(...,funcp)
> {
>   matrices <- list(...);
>   n.matrices <- length( matrices );
>   # What should I put here?!?! -------------------------------------
> }
> 
> 
> 
> --
> View this message in context: 
> http://www.nabble.com/n-dimensional-vector-operations-tp231476
> 07p23147607.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
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> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
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