Re: [R] Applying a function to each element of an array

From: Tuszynski, Jaroslaw W. <JAROSLAW.W.TUSZYNSKI_at_saic.com>
Date: Sat 08 Oct 2005 - 05:17:46 EST


I suspect that loop would be the fastest since it would have the least memory overhead. You do not want to have too many internal copies of 7000x7000 matrices.

 Jarek

====================================================\==== 
 Jarek Tuszynski, PhD.                           o / \ 
 Science Applications International Corporation  <\__,|  
 (703) 676-4192                                   ">  \ 
 Jaroslaw.W.Tuszynski@saic.com                     `   \ 

 

-----Original Message-----
From: r-help-bounces@stat.math.ethz.ch
[mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Tim Smith Sent: Friday, October 07, 2005 2:48 PM
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                 


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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 Received on Sat Oct 08 05:20:18 2005

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