Scott: Your problem specification is rather vague: What do you mean by "use"?
In general, matrices are merely vectors with a dim attribute, so if you can do what you want with them as vectors, then that will work for them as matrices. For example: > m1<- matrix(1:6, nr=3) > m2 <- matrix(11:16, nr=2) > m2*m2 [,1] [,2] [,3] [1,] 121 169 225 [2,] 144 196 256 If this does not meet your needs, you will have to follow the posting guide and provide both code and a minimal reproducible example. Cheers, Bert Bert Gunter Genentech Nonclinical Biostatistics (650) 467-7374 "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." H. Gilbert Welch On Wed, Apr 30, 2014 at 10:54 AM, Waichler, Scott R <scott.waich...@pnnl.gov> wrote: > Hi, > > I want to apply a custom function to all the elements of one matrix. The > function uses the value in the same i,j in a second matrix. How can I use > apply() or similar function to avoid nested loops in i and j? > > Thanks, > Scott Waichler > Pacific Northwest National Laboratory > Richland, WA, USA > > ______________________________________________ > R-help@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. ______________________________________________ R-help@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.