Re: [R] How to 'explode' a matrix

2011-01-05 Thread Kevin Ummel
Thanks, Henrique. The second option you suggested is about twice as fast as my original application. Much appreciated, Kevin On Jan 5, 2011, at 6:30 PM, Henrique Dallazuanna wrote: > Try this: > > apply(apply(m, 2, rep, each = 2), 1, rep, each = 2) > > or > > m[rep(seq(nrow(m)), each = 2),

Re: [R] How to 'explode' a matrix

2011-01-05 Thread Jorge Ivan Velez
Hi Kevin, Take a look at ?kronecker HTH, Jorge On Wed, Jan 5, 2011 at 7:03 AM, Kevin Ummel <> wrote: > Hi everyone, > > I'm looking for a way to 'explode' a matrix like this: > > > matrix(1:4,2,2) > [,1] [,2] > [1,]13 > [2,]24 > > into a matrix like this: > > > matrix(c(1,

Re: [R] How to 'explode' a matrix

2011-01-05 Thread Ben Bolker
Kevin Ummel gmail.com> writes: > I'm looking for a way to 'explode' a matrix like this: > > > matrix(1:4,2,2) > [,1] [,2] > [1,]13 > [2,]24 > 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)) ch

Re: [R] How to 'explode' a matrix

2011-01-05 Thread Henrique Dallazuanna
Try this: apply(apply(m, 2, rep, each = 2), 1, rep, each = 2) or m[rep(seq(nrow(m)), each = 2), rep(seq(ncol(m)), each = 2)] On Wed, Jan 5, 2011 at 10:03 AM, Kevin Ummel wrote: > Hi everyone, > > I'm looking for a way to 'explode' a matrix like this: > > > matrix(1:4,2,2) > [,1] [,2] > [1

[R] How to 'explode' a matrix

2011-01-05 Thread Kevin Ummel
Hi everyone, I'm looking for a way to 'explode' a matrix like this: > matrix(1:4,2,2) [,1] [,2] [1,]13 [2,]24 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,]1133 [2,]1133 [3,]22