From: RAVI VARADHAN <rvaradhan_at_jhmi.edu>

Date: Wed 31 Jan 2007 - 12:41:39 GMT

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 and provide commented, minimal, self-contained, reproducible code. Received on Wed Jan 31 23:57:05 2007

Date: Wed 31 Jan 2007 - 12:41:39 GMT

Hi,

I have two matrices A (m x 2) and B (n x 2), where m and n are large integers (on the order of 10^4). I am looking for an efficient way to create another matrix, W (m x n), which can be defined as follows:

for (i in 1:m){

for (j in 1:n) {

W[i,j] <- g(A[i,], B[j,])

*} }
*

I have tried the following and it works okay, but I am sure that I can do even better:

for (i in 1:m) {

W[i,] <- apply(B, 1, y=A[i,], function(x,y) g(y,x))

*}
*

How can I do this in a faster manner (for example, I feel that I should be able to use "outer")?

Thanks for any suggestions.

Best,

Ravi.

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 and provide commented, minimal, self-contained, reproducible code. Received on Wed Jan 31 23:57:05 2007

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