Yes, I first came across the bug testing the equivalence of the expressions +/.* and (+/ @: *)" 1 _ from Learning J 22 .4
a=. >1 0 2; _1 3 1 b=. >3 1; 2 1;1 0 a (+/ @: *)" 1 _ b 7 3 4 2 a +/ .* b 5 1 4 2 On Fri, Aug 20, 2010 at 3:28 PM, Roger Stokes < [email protected]> wrote: > 9 !: 14 '' > j701/beta/2010-03-31/11:40 > > 1 0 2 (+/ @: *) (3 2 $ 3 1 2 1 1 0) > 7 3 > > NB. This result is wrong, surely. > > NB. The correct result is 5 1, shown by replacing + > NB. with an equivalent verb, say +"0 0 . > > 1 0 2 ((+"0 0) / @: *) (3 2 $ 3 1 2 1 1 0) > 5 1 > > NB. In J504, both of the above expressions give > NB. the same result, 5 1 > > > NB. This has been mentioned before, firstly in a posting by > NB. Patrick Van Beek, with similar example. > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
