From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>

Date: Sat 08 Oct 2005 - 05:28:17 EST

Date: Sat 08 Oct 2005 - 05:28:17 EST

If A is the matrix the answer is 2*(1 - 2^(-A)), which took about 10secs for an example of your size.

*>From \sum_{i=1}^n x^{1-i} = (1-x^{-n})/(1-x), E & OE.
*

On Fri, 7 Oct 2005, Tim Smith wrote:

> 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?
*

-- Brian D. Ripley, ripley@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ 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.htmlReceived on Sat Oct 08 05:34:30 2005

*
This archive was generated by hypermail 2.1.8
: Fri 03 Mar 2006 - 03:40:39 EST
*