The sum in the loop is simply: 2 - (0.5)^count. So you don't need this loop. As "count" gets large, the sum approaches 2.
Ravi. > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:r-help- > [EMAIL PROTECTED] On Behalf Of Patrick Burns > Sent: Friday, October 07, 2005 4:29 PM > To: Tim Smith > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] Applying a function to each element of an array > > If there weren't an analytic solution to your problem, > then you could build a vector of the answers from 1 > to the maximum in the matrix. Call that 'wtvec'. Then: > > ans <- array(NA, dim(A), dimnames(A)) > ans[] <- wtvec[as.vector(A)] > > should get you what you want. > > > Patrick Burns > [EMAIL PROTECTED] > +44 (0)20 8525 0696 > http://www.burns-stat.com > (home of S Poetry and "A Guide for the Unwilling S User") > > Tim Smith wrote: > > >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 ______________________________________________ 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