Isn't atan2 =: 12&o.@j./~
a very good candidate for inclusion in math/misc/trig.ijs ? On Wed, Mar 12, 2014 at 4:07 AM, Tom Arneson <[email protected]> wrote: > The circle verb o. with 12 as the left argument > > NB. radian to degree > r2d=: 180p_1*[ > > atan2=: 12&o. > > [r=. atan2 0j0 1j1 0j1 _1j1 _1j0 _1j_1 0j_1 1j_1 1j0 > 0 0.785398 1.5708 2.35619 3.14159 _2.35619 _1.5708 _0.785398 0 > > r2d r > 0 45 90 135 180 _135 _90 _45 0 > > 360|r2d r > 0 45 90 135 180 225 270 315 0 > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Raul Miller > Sent: Tuesday, March 11, 2014 19:00 > To: Programming forum > Subject: Re: [Jprogramming] atan2 ? > > 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 > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
