If you really are converting random boolean values to (1,_1) values, another possibility is _1&^ or _1^]; i.e. 0 to 1 and 1 to _1.
On Mon, Dec 10, 2012 at 8:58 PM, Brian Schott <schott.br...@gmail.com>wrote: > timespacex > 6!:2 , 7!:2@] > am =:_1& (I.@:-.@]}) > am2=: ((-&1) @ +:) > amd=: <:@:+: > aml=: _1 + +: > d=: 2 6 50000?.@$ 2 > timespacex 'am"1 d' > 0.011278 1.05535e7 > timespacex 'am2 d' > 0.187884 8.39091e6 > timespacex 'amd d' > 0.004365 1.6779e7 > timespacex 'aml d' > 0.004874 1.67789e7 > > It looks like David's method is fastest and Peter's is most lean. > And Linda's method loses nothing relative to David's. > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
