Array arithmetic

no, it won't.

 you're doing the right math on the "valid" subset... but you're not
 returning the zeros where needed.... therefore, the whole thing will
 get recycled to match the dimensions.


 b


 On Mar 6, 2008, at 2:03 PM, Henrique Dallazuanna wrote:

 > I think this should work:
 >
 > array(A[abs(B) > 10e-5]/B[abs(B) > 10e-5], dim=c(L, M, N, P))
 >
 > On 06/03/2008, Gang Chen <gangchen6 at gmail.com> wrote:

 >> I have two arrays A and B with dimensions of (L, M, N, P) and (L, M,
 >> N), and I want to do
 >>
 >> for (i in 1:L) {
 >> for (j in 1:M) {
 >> for (k in 1:N) {
 >>   if (abs(B[i, j, k]) > 10e-5)  C[i, j, k,] <- A[i, j, k,]/B[i, j, k]
 >>   else C[i, j, k,] <- 0
 >> }
 >> }
 >> }
 >>
 >> How can I get C more efficiently than looping?
 >>
 >> Thanks,
 >> Gang
 >>
 >> ______________________________________________
 >> R-help at 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

 >
 >
 > --
 > Henrique Dallazuanna
 > Curitiba-Paran?-Brasil
 > 25? 25' 40" S 49? 16' 22" O
 >
 > ______________________________________________
 > R-help at 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