5 messages · Kevin Ummel, Henrique Dallazuanna, Ben Bolker +1 more
Hi everyone, I'm looking for a way to 'explode' a matrix like this:
matrix(1:4,2,2)
[,1] [,2] [1,] 1 3 [2,] 2 4 into a matrix like this:
matrix(c(1,1,2,2,1,1,2,2,3,3,4,4,3,3,4,4),4,4)
[,1] [,2] [,3] [,4] [1,] 1 1 3 3 [2,] 1 1 3 3 [3,] 2 2 4 4 [4,] 2 2 4 4 My current kludge is this: v1=rep(1:4,each=2,times=2) v2=v1[order(rep(1:2,each=4,times=2))] matrix(v2,4,4) But I'm hoping there's a more efficient solution that I'm not aware of. Many thanks, Kevin
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Kevin Ummel <kevinummel <at> gmail.com> writes:
I'm looking for a way to 'explode' a matrix like this:
matrix(1:4,2,2)
[,1] [,2] [1,] 1 3 [2,] 2 4
This is the Kronecker product of your matrix with the
matrix (1 1 ; 1 1)
m <- matrix(1:4,2,2)
kronecker(m,matrix(1,2,2))
cheers
Ben Bolker
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