There are some cheeky (or is it cheesy?) versions: (2*a) %~ (-b) (+,-) %: (b^2) - 4*a*c NB. Kip Murray (2*a) %~ - b (+,-) %: (b^2) - 4*a*c (+:a) %~ - b (+,-) %: (*:b) - 4*a*c -: a %~ - b (+,-) %: (*:b) - 4*a*c
On Tue, Dec 11, 2012 at 11:37 AM, km <[email protected]> wrote: > It appears this could be translated into J as the rather cool > > (2*a) %~ (-b) (+,-) %: (b^2) - 4*a*c > > Sent from my iPad > > > On Dec 11, 2012, at 12:59 PM, Roger Hui <[email protected]> wrote: > > > Example from the Iverson and McDonnell *Phrasal > > Forms*<http://www.jsoftware.com/papers/fork.htm>paper (which > > introduced fork): > > > > (-b)(+,-)√((b*2)-4×a×c)÷2×a > > > > √ is a postulated APL primitive, spelled %: in J. > > > > > > > > > > On Tue, Dec 11, 2012 at 10:49 AM, km <[email protected]> wrote: > > > >> What is the coolest way of programming the quadratic formula in J? We > are > >> finding the roots of polynomial c + x*(b + x*a) without using p. . I > offer > >> > >> roots > >> 3 : 0 > >> 'a b c' =. y > >> q =. %: (b^2) - 4*a*c > >> (2*a) %~ (-b) + q,-q > >> ) > >> roots 1 3 2 > >> _1 _2 > >> roots 1 0 1 > >> 0j1 0j_1 > >> roots 1 _2 1 > >> 1 1 > >> > >> partly as problem definition. I am looking for cool roots verbs! > >> > >> Kip Murray > >> > >> Sent from my iPad > >> > >> ---------------------------------------------------------------------- > >> 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
