we can build internal representation (3!:1 or 3) of the box array and convert it using 3!:2, not sure if this can improve time or space efficiency.
On Mon, Mar 10, 2014 at 2:37 PM, Raul Miller <[email protected]> wrote: > Since using , to build boxed arrays does not currently have any code to > support it, time is O(n^2). In other words: inefficient for long lists of > boxes. > > So let's say we wanted to build lists of 30000 boxes, how could we do that > efficiently? > > It seems to me that the right thing to do would be: pick a threshold (maybe > 1000 boxes) and when your list gets that long, append that intermediate > result to a result list and start a fresh instance of the working list. > Repeat until done (and don't forget to append the last intermediate list to > the result). > > Conceptually speaking, this is still O(n^2). But it should also be orders > of magnitude faster (at the cost of some complexity) than use of unadorned > comma. (And conceptually speaking one might be able to define some kind of > "infinite" representation of this algorithm which has better than O(n^2) > performance. Maybe O(n log n)? > > Thanks, > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
