try a simple for loop, it will be fast enough in this case, e.g.,
matSums <- function (lis) {
out <- array(data = 0, dim = dim(lis[[1]]))
for (i in seq(along = lis))
out <- out + lis[[i]]
out
}
a <- b <- c <- d <- matrix(1:4, 2, 2)
l <- list(a, b ,c, d)
matSums(l)
I hope it helps.
Best,
Dimitris
----
Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
----- Original Message -----
From: "Shubha Vishwanath Karanth" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, June 04, 2008 4:53 PM
Subject: [R] sum of unknown number of matrices
Hi R,
I have a list of matrices. I need to get the sum of all the matrices
in
the list.
Example:
a=b=c=d=matrix(1:4,2,2)
l=list(a,b,c,d)
I need:
a+b+c+d
[,1] [,2]
[1,] 4 12
[2,] 8 16
Something like do.call("+",l) is not working...why is this?
I may not be knowing the number of matrices in the list...
Thanks, Shubha
This e-mail may contain confidential and/or privileged
i...{{dropped:13}}
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