[R] multiplication question

From: Murali Menon <feanor0_at_hotmail.com>
Date: Wed, 02 Jul 2008 16:30:46 +0000

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 compute  

Sum (X[i] * Y[j])
i != j  

where i != j  

also, what if i wanted  

Sum (X[i] * Y[j] * R[i, j])
i != j  

where R is a matrix?  

thanks,  

murali    



Enter the Zune-A-Day Giveaway for your chance to win day after day after day

M_Mobile_Zune_V1

        [[alternative HTML version deleted]]



R-help_at_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. Received on Wed 02 Jul 2008 - 20:34:10 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Tue 08 Jul 2008 - 00:31:58 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive