Here's a more general approach: rd=: (+ - ]) 1j1 * |
-- Raul On Wed, May 2, 2012 at 6:11 AM, Bo Jacoby <bojac...@yahoo.dk> wrote: > Hello J'ers > > Even if a complex number is actually real it may display nonzero imaginary > part because of round-off errors. Adding and subtracting 1e6j1e6 removes the > round-off error, but is there a better or more general solution? > > UM=.%:%~_1^]%~[:+:[:*/~i. NB. Unitary Matrix generator > > rd=.]&.(1e6j1e6&+) NB. round-off cleaner > > u=.n+/ .*+n=.UM 3 NB. unit matrix > > u NB. ugly display > 1 _2.78e_17j_1.11e_16 1.11e_16j_2.22e_16 > _2.78e_17j1.11e_16 1 _2.78e_17j_1.11e_16 > 1.11e_16j2.22e_16 _2.78e_17j1.11e_16 1 > > rd u NB. nice display > 1 0 0 > 0 1 0 > 0 0 1 > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
