Does this do what you want:
> x <- matrix(1:36,6)
> x
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 7 13 19 25 31
[2,] 2 8 14 20 26 32
[3,] 3 9 15 21 27 33
[4,] 4 10 16 22 28 34
[5,] 5 11 17 23 29 35
[6,] 6 12 18 24 30 36
> # create indices (going to assume an even number of rows
> x.ind <- seq(1, nrow(x), by=2)
> t(sapply(x.ind, function(.ind) x[.ind,] * x[.ind+1,]))
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 2 56 182 380 650 992
[2,] 12 90 240 462 756 1122
[3,] 30 132 306 552 870 1260
>
On Sun, Jul 27, 2008 at 6:20 PM, rcoder <[EMAIL PROTECTED]> wrote:
>
> Hi everyone,
>
> I want to perform an operation on a matrx that outputs the product of
> successive pairs of rows. For example: calculating the product between rows
> 1 & 2; 3 & 4; 5 & 6...etc.
>
> Does anyone know of any readily available functions that can do this?
>
> Thanks,
>
> rcoder
>
>
> --
> View this message in context:
> http://www.nabble.com/product-of-successive-rows-tp18681259p18681259.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
> and provide commented, minimal, self-contained, reproducible code.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem you are trying to solve?
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