[R] elegant matrix creation

Robin Hankin rksh at soc.soton.ac.uk
Wed Jul 28 16:49:19 CEST 2004

```Spencer

thank you!

just what I wanted.   I have a feeling that jj3 is qualitatively
different from the other two.
Nevertheless, I'm sure it'll crack sooner or later!

best wishes

rksh

At 07:34 am -0700 28/07/04, Spencer Graves wrote:
>      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
>>have
>>
>>jj1 <-
>>structure(c(1,2,3,1,2,3,1,2,3,1,2,3,1,2,3,1,2,
>>3,1,2,3,1,2,3,1,2,3,2,3,1,2,3,1,2,3,1,2,3,
>>1,2,3,1,2,3,1,2,3,1,2,3,1,2,3,1,3,1,2,3,1,
>>2,3,1,2,3,1,2,3,1,2,3,1,2,3,1,2,3,1,2,3,1,
>>2),.Dim = as.integer(c(9,9)))
>>
>>[ image(jj1) is good here ] then I can get this with
>>
>>kronecker(matrix(1,3,1),kronecker(1+outer(0:2,0:2,"+")%%3,matrix(1,1,3)))
>>
>>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,
>>1,2,3,1,2,3,1,2,3,3,1,2,3,1,2,3,1,2,1,2,3,1,2,
>>3,1,2,3,3,1,2,3,1,2,3,1,2,2,3,1,2,3,1,2,3,1,3,
>>1,2,3,1,2,3,1,2,2,3,1,2,3,1,2,3,1),9,9)
>>
>>jj3 <- structure(c(1,2,3,2,3,1,3,1,2,1,2,1,2,3,2,3,1,
>>3,1,3,1,2,1,2,3,2,3,2,3,1,3,1,2,1,2,3,2,3,
>>2,3,1,3,1,2,1,2,1,2,3,2,3,1,3,1,3,1,2,1,2,
>>3,2,3,1,3,1,3,1,2,1,2,3,2,3,2,3,1,3,1,2,1, 2),.Dim =
>>as.integer(c(9,9)))
>>
>>[ 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?
>>
>>

--
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
SO14 3ZH
tel +44(0)23-8059-7743
initialDOTsurname at soc.soton.ac.uk (edit in obvious way; spam precaution)

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