Thanks for your help, folks. The sum of (outer product less the diagonal) works. (In the original post, I guess I should have specified 'pair-wise product' of two vectors to be clearer).
Date: Thu, 3 Jul 2008 00:25:10 +0300From: [EMAIL PROTECTED]: [EMAIL PROTECTED]: Re: [R] multiplication questionCC: [EMAIL PROTECTED] example ...x <- 1:5 ; y<- 6:8(m <- x %o% y) # is this what you mean by product of two vectors?sum(m[row(m)!=col(m)]) # or ...sum(m)-sum(diag(m)) On Wed, Jul 2, 2008 at 7:30 PM, Murali Menon <[EMAIL PROTECTED]> wrote: folks,is there a clever way to compute the sum of the product of two vectors such that the common indices are not multiplied together?i.e. if i have vectors X, Y, how can i computeSum (X[i] * Y[j])i != jwhere i != jalso, what if i wantedSum (X[i] * Y[j] * R[i, j])i != jwhere R is a matrix?thanks,[EMAIL PROTECTED] mailing listhttps://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code. _________________________________________________________________ [[elided Hotmail spam]] [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org 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.
