On Thu, Dec 22, 2011 at 5:54 AM, Henry Rich <henryhr...@nc.rr.com> wrote: > Note that > > c}b,:a > > does indeed compute b,:a. But if it's used in the precise form > > result =: c}b,:a > > the computation is avoided. > > b =: 1e6$4 > a =: 1e6$4 > c=: ? 1e6$ 2 > ts 'c}b,:a' > 0.0401299 2.09725e7 > ts 'q =: c}b,:a' > 0.0112949 4.19558e6 > > There are other special cases; see the Special Code page.
Especially the "in-place" case where items of b or a are altered in-place. Note that timespacex is defined in the stdlib in J7. timespacex ' c}b,:a' 0.0229656 4.19451e7 timespacex 'q=: c}b,:a' 0.00915218 8.39091e6 timespacex 'b=: c}b,:a' 0.00612322 2304 timespacex 'b=: c}b,:a' 0.00612322 2304 timespacex 'b=: c}a,:b' 0.00615121 2304 timespacex 'a=: c}b,:a' 0.00612789 2304 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
