[Jprogramming] Cool roots

[Yuvaraj Athur Raghuvir]

Hello Edward,

Is there a PDF version that I can download? It seems that the link you have
offered takes me to the edit mode on the document.

Thanks,
Yuvaraj


On Tue, Dec 11, 2012 at 4:21 PM, Edward Mokurai Cherlin <
mokurai at sugarlabs.org> wrote:

> On Tue, December 11, 2012 1:49 pm, km 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 can't claim the coolest implementation, but you should certainly be
> aware of my work on a J edition of Iverson's Algebra: An Algorithmic
> Treatment. It also has working code for solving cubics and quartics
> apart from p. .
>
> booki.treehouse.su/algebra-an-algorithmic-treatment/_v/1.0/edit/
>
>    qe=.3 : 0
> ('c';'b';'a')=.y
> ((-b)+(1 _1*%:(*:b)-4*a*c))%2*a
> )
>
> >  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
>
> --
> Edward Mokurai (默雷/निशब्दगर्ज/نشبدگرج) Cherlin
> Silent Thunder is my name, and Children are my nation.
> The Cosmos is my dwelling place, the Truth my destination.
> http://wiki.sugarlabs.org/go/Replacing_Textbooks
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>