[R-sig-hpc] number of combinations

[Amen Alyaari]

Hello All,

I have three datasets and would like to know how much N was used in my 
calculations.

I read the data into a multi-dimensional array with dimensions (nx, ny, 
ntsteps, ndatasets), e.g. with a smaller example dataset:

                               # nx   ny   nsteps ndatasets
             dat = runif(20 * 30 * 100 *  3)
         dim(dat) = c(20, 30, 100, 3)
 > str(dat)
     num [1:20, 1:30, 1:100, 1:3] 0.1834 0.8537 0.0672 0.0734 0.8078 ...
we take advantage of the cor functions and build this function to 
compute how many N we have:

     cor_withN <- function(...) {
         res <- try(cor.test(...)$parameter+2, silent=TRUE)
         ifelse(class(res)=="try-error", NA, res)}
Now we take advantage of the fact that apply also works on 
multi-dimensional arrays, not only matrices:
We use apply to iterate over all the x,y,z triples.

       result = apply(dat, c(1,2), function(x) cor_withN(x[,1], 
x[,2],x[,3]))
 > str(cor_result)
      logi [1:20, 1:30] NA NA NA NA NA NA ..
so something is wrong by getting NA NA NA NA
if the last line went well! then:      str(cor_result)                   
should be:

      logi [1:20, 1:30] 100 100 100 100 100 ..(nsteps)
Any idea on why I am getting NA or is there another way to do it?

When I tested it with 2 datsets,it went well!

       cor_result = apply(dat, c(1,2), function(x) cor_withN(x[,1], x[,2]))
 > str(cor_result)
      num [1:20, 1:30] 100 100 100 100 100 100 100 100 100 100
so the problem is when I added x[,3]!! Thanks

Thanks alot