Well, since Sum(i=1 to i-n) =n*(n+1)/2, your loop simply gives 1/4*count*(count-1). So if your matrix is A, A*(A-1)/4 is about the quickest way to get your answer I think.
-- Bert Gunter Genentech Non-Clinical Statistics South San Francisco, CA "The business of the statistician is to catalyze the scientific learning process." - George E. P. Box > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Tim Smith > Sent: Friday, October 07, 2005 11:48 AM > To: r-help@stat.math.ethz.ch > Subject: [R] Applying a function to each element of an array > > Hi, > > I have a 7000x7000 matrix, and each element is an integer. > For each element, I want to apply the function : > > wt <- 0 > for(q in 1:count){ > wt <- wt + 0.5^(q-1) > } > > I get the value of 'count' from the elements in the matrix , > and want to store the corresponding 'wt' value for that element. > > I suppose I could loop through the matrix, and apply the > function to each element but this would take a really really > long time. Are there any quicker ways to get the same result? > > many thanks, > > Tim > > > --------------------------------- > > > [[alternative HTML version deleted]] > > ______________________________________________ > 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 > ______________________________________________ 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