Thanks for the info. Unfortunately its a little bit slower after one apples
to apples test using my big data. Mine: 0.28 seconds. Yours. 0.73 seconds.
Not a big deal, but significant when I have to do this 300 to 500 times.

regards,

ben

On Fri, Mar 9, 2012 at 1:23 PM, Rui Barradas <rui1174@sapo.pt> wrote:

> Hello,
>
> I don't know if it's the fastest but it's more natural to have an index
> matrix with two columns only,
> one for each coordinate. And it's fast.
>
> fun <- function(valdata, inxdata){
>        nr <- nrow(inxdata)
>        nc <- ncol(inxdata)
>        mat <- matrix(NA, nrow=nr*nc, ncol=2)
>        i1 <- 1
>        i2 <- nr
>        for(j in 1:nc){
>                mat[i1:i2, 1] <- inxdata[, j]
>                mat[i1:i2, 2] <- rep(j, nr)
>                i1 <- i1 + nr
>                i2 <- i2 + nr
>        }
>        matrix(valdata[mat], ncol=nc)
> }
>
> fun(vals, indx)
>
> Rui Barradas
>
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Re-index-values-of-one-matrix-to-another-of-a-different-size-tp4458666p4460575.html
> Sent from the R help mailing list archive at Nabble.com.
>
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