[R] elegant matrix creation

Spencer Graves spencer.graves at pdf.com
Wed Jul 28 16:34:00 CEST 2004

      It's not obvious what pattern you want, but some variants of the 
following would work for jj1 and jj2: 

      1+outer(1:9, 1:9, "+")%%3

In particular the following are equal to your jj1 and jj2:  

jj1. <- 1+outer(0:8, rep(0:2, e=3), "+")%%3

jj2. <- 1+outer(0:8, c(1,2,1,3,1,3,2,3,2)-1, "+")%%3     

      I couldn't figure out jj3, but this system may not work so easily 
for that.  hope this helps.  spencer graves

Robin Hankin wrote:

>Hello everybody.
>I am trying to reproduce a particular matrix in an elegant way.  If I
>jj1 <-
>2),.Dim = as.integer(c(9,9)))
>[ image(jj1) is good here ] then I can get this with
>I want to reproduce the following matrices in an equivalent way:
>jj2 <- matrix(c(1,2,3,1,2,3,1,2,3,2,3,1,2,3,1,2,3,1,
>jj3 <- structure(c(1,2,3,2,3,1,3,1,2,1,2,1,2,3,2,3,1,
>3,2,3,1,3,1,3,1,2,1,2,3,2,3,2,3,1,3,1,2,1, 2),.Dim =
>[ note that jj1-jj3 each have precisely 3 occurrences of A, B, and C
>along each row, column and (broken) diagonal ].
>Can anyone give me a nice elegant way of creating jj2 and jj3 please?

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