On 9/28/07, Roger Hui <[EMAIL PROTECTED]> wrote: > (1000$0) x:@+//. 1000$2^50 > 1125899906842623744 > (1000$0) +//. x: 1000$2^50 > 1125899906842624000
I cannot think of any reason, other than special code, for this difference. (And I think you will not get that first result with your j602 code base.) Without special code, that first expression should be equivalent to n=:2^50 n+x:n+x:n+x:n+...x:n+n In other words, without special code, the first intermediate result would use floating point representation and every subsequent intermediate result would use arbitrary precision representation And, with this value for n (x:n+n) -: n+&x:n 1 That said, if special code prevents x:@+/ from functioning in this fashion, that might account for the speed difference. (but does not account for why x: was necessary). In other words -- if you are correct (and I don't have any reason to suspect you are not), then there's mysterious things happening. -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
