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 <rogerhui.can...@gmail.com> 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 <k...@math.uh.edu> 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
