From: Berwin A Turlach <berwin_at_maths.uwa.edu.au>

Date: Wed 13 Jul 2005 - 19:37:37 EST

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R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Jul 13 19:41:30 2005

Date: Wed 13 Jul 2005 - 19:37:37 EST

>>>>> "RH" == Robin Hankin <r.hankin@noc.soton.ac.uk> writes:

RH> I want to write a little function that takes a matrix X of RH> size m-by-n, and a list L of length "m", whose elements are RH> matrices all of which have the same number of columns but RH> possibly a different number of rows.

RH> I then want to get a sort of dumbed-down kronecker product in which RH> X[i,j] is replaced by X[i,j]*L[[j]]

RH> where L[[j]] is the j-th of the "m" matrices. For example, if

RH> X = matrix(c(1,5,0,2),2,2)

RH> and

RH> L[[1]] = matrix(1:4,2,2)

RH> L[[2]] = matrix(c(1,1,1,1,1,10),ncol=2)

RH> I want

RH> [,1] [,2] [,3] [,4] RH> [1,] 1 3 0 0 RH> [2,] 2 4 0 0 RH> [3,] 5 5 2 2 RH> [4,] 5 5 2 2 RH> [5,] 5 50 2 20

> tmp <- sapply(1:length(L), function(j, mat, list) kronecker(X[j,,drop=FALSE], L[[j]]), mat=X, list=L)

> do.call("rbind", tmp)

[,1] [,2] [,3] [,4]

[1,] 1 3 0 0 [2,] 2 4 0 0 [3,] 5 5 2 2 [4,] 5 5 2 2 [5,] 5 50 2 20

**HTH.
**
Cheers,

Berwin

- Full address ============================
Berwin A Turlach Tel.: +61 (8) 6488 3338 (secr)
School of Mathematics and Statistics +61 (8) 6488 3383 (self)
The University of Western Australia FAX : +61 (8) 6488 1028
35 Stirling Highway
Crawley WA 6009 e-mail: berwin@maths.uwa.edu.au
Australia http://www.maths.uwa.edu.au/~berwin

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Jul 13 19:41:30 2005

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