See https://en.wikipedia.org/wiki/Atan2#Definition_and_computation
On Tue, Mar 11, 2014 at 4:59 PM, Raul Miller <[email protected]> wrote: > This might be what you are looking for? > atan2trivial=: _3 o. %~ > atan2=: 0 { [: +. [: r.^:_1 j. > > For the principal domain, atan2trivial matches atan2 > 1 (atan2trivial -: atan2) 2 > 1 > > However, atan2 can distinguish direction when x=0 > 0 atan2 1 > 1.5708 > 0 atan2 _1 > _1.5708 > > I'd like more test cases, though. I've not been doing much trig recently, > and it's possible I made a mistake. > > Maybe someone who has been working with this kind of math can judge from > what viewmat displays? > > require 'viewmat' > viewmat atan2"0/~ i:100 > > Thanks, > > -- > Raul > > > > > On Tue, Mar 11, 2014 at 7:05 PM, EelVex <[email protected]> wrote: > > > Is there an atan2 anywhere in some library? > > > > If not maybe we could add it? > > > > A simple start could be: > > atan2 =: +:@(_3&o.)@([ %~ ] -~ +/&.:*:) > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
