thank you for another phrase.  Will take a close look at it as well.

Elijah, you're absolutely right - it was my typo. I'm shocked, considering
I didn't detect this in my studies over the last few weekends.  Need to
re-check my study notes - I may be able to use more verbs now.  Thanks for
pointing it out.

have a good day!


Maurice

On Sun, Oct 24, 2021 at 2:19 AM ethiejiesa via Programming <
[email protected]> wrote:

> FWIW, this alternate phrasing of the rt verb is also possible.
>
>     rt=: (%: -)~ * ^@(%~ 0j1p1+0j2p1*i.)@]
>
> Elijah Stone <[email protected]> wrote:
> > - is always a verb, which negates its right argument.  -1 0 1 is - (1 0
> > 1), or _1 0 _1; so p. solves -x^2 - 1 = 0.  I expect you want _1 0 1.
> >
> >   -E
> >
> > On Sun, 24 Oct 2021, More Rice wrote:
> >
> > > Thank you Elijah.  There is a lot for me to unpack in your approach.  I
> > > need a cup of coffee and chew on it deeply in the morning.
> > >
> > > Thanks again Raul.  I looked at the p. verb before - this verb feels
> kind
> > > of strange.
> > >
> > > For this specific case (x^6+1=0) and the example in NuVoc, they work
> > > nicely!  I tried something even simpler when I first saw it:  x^2 - 1
> = 0.
> > > The answer looks very strange.
> > >
> > >   p. -1 0 1
> > > +--+--------+
> > > |_1|0j1 0j_1|
> > > +--+--------+
> > >
> > > So, I have always thought the p. verb is designed for a special kind of
> > > polynomial which I don't currently understand, and opted to use the
> Euler
> > > formula based approach instead.
> > >
> > > Or am I using the p. wrong?
> > >
> > >
> > > Maurice
> > >
> > > On Sat, Oct 23, 2021 at 9:00 PM Elijah Stone <[email protected]>
> wrote:
> > >
> > >> Here is a fun party trick:
> > >>
> > >>     rt=. (] %: -@[) * [: ^ [: j. ] %~ 1p1 + 2p1 * i.@]
> > >>     pw=. ^ :. rt
> > >>     f=. 1 + ] pw 6:
> > >>     (f^:_1) 0
> > >> 0.866025j0.5 6.12323e_17j1 _0.866025j0.5 _0.866025j_0.5
> _1.83697e_16j_1
> > >> 0.866025j_0.5
> > >>     f (f^:_1) 0
> > >> _2.22045e_16j6.10623e_16 0j3.67394e_16 _2.22045e_16j_6.10623e_16
> > >> _2.22045e_16j2.05391e_15 0j1.10218e_15 0j3.10862e_15
> > >>
> > >> (Sadly, the inverter is not smart enough to invert e.g. 1 + pw&3 +
> pw&6,
> > >> so p. is probably the more practical solution.)
> > >>
> > >>   -E
> > >>
> > >> On Sat, 23 Oct 2021, More Rice wrote:
> > >>
> > >> > Thank you for the notes - I'll keep it in my bookmark as reference!
> > >> >
> > >> > I started out this morning with my pre-calculus book trying to
> practice J
> > >> > sentences with.  I wanted the numeric answers for complex roots.
> Like:
> > >> >
> > >> > // matlab version
> > >> > syms x
> > >> > eqn = x^6+1 == 0
> > >> > solve(eqn, x)
> > >> >
> > >> > But, it seems J only gives the principal root (?), not all 6 of
> them; so,
> > >> > another opportunity for practise.  But, I ended up writing like ...
> > >> > "matlab":
> > >> >
> > >> >   ^ 0j1 * (1p1 + 2p1 * i.6) % 6  NB. 1st version
> > >> >
> > >> > That was why I was browsing NuVoc, looking for examples/ideas,
> hoping to
> > >> > see something to make my J sentence looks more ... "J-idiomatic"
> (while
> > >> > learning something out of the process).
> > >> >
> > >> > This is all I can I come up with today:
> > >> >
> > >> >   ^ 0j1 * 6 %~ 1p1 + 2p1 * i.6   NB. 2nd version
> > >> >
> > >> > How would the same answer look like in the eyes of J Masters?
> > >> >
> > >> >
> > >> > thanks for your thoughts.
> > >> >
> > >> > On Sat, Oct 23, 2021 at 4:18 PM 'Pascal Jasmin' via Programming <
> > >> > [email protected]> wrote:
> > >> >
> > >> >> a more hollistic explanation,
> > >> >>
> > >> >> Most conjunctions, and including the & and @ famillies, produce
> verb
> > >> >> phrases when bound.  A verb or verb phrase can/has to produce
> different
> > >> >> results/computations depending on monadic or dyadic cases.  In u@v,
> u
> > >> is
> > >> >> always monadic, and v is ambivalent.  in u&v, v is always monadic,
> and
> > >> u is
> > >> >> the valence of the verb phrase.
> > >> >>
> > >> >> A missing "composing conjunction" in J is ([ u v)  where u is
> always
> > >> >> dyadic and v is ambivalent.  But the fact that it is easy to write
> as a
> > >> >> fork suggests a dedicated conjunction is not needed.
> > >> >>
> > >> >>
> > >> >> On Saturday, October 23, 2021, 03:30:09 p.m. EDT, Raul Miller <
> > >> >> [email protected]> wrote:
> > >> >>
> > >> >>
> > >> >>
> > >> >>
> > >> >>
> > >> >> https://www.jsoftware.com/help/dictionary/d631.htm
> > >> >>
> > >> >>   x u&.v y ↔ vi (v x) u (v y)
> > >> >>
> > >> >> Here:
> > >> >>   u is +
> > >> >>   v is *:
> > >> >>   vi is %: (or *:inv)
> > >> >>   x is 3
> > >> >>   y is 4
> > >> >>
> > >> >> So these are equivalent
> > >> >>   3 +&.*: 4
> > >> >>   %: (*:3) + (*: 4)
> > >> >>   *:inv (*:3) + (*: 4)
> > >> >>
> > >> >> I hope this makes sense.
> > >> >>
> > >> >> --
> > >> >> Raul
> > >> >>
> > >> >> On Sat, Oct 23, 2021 at 3:03 PM More Rice <[email protected]>
> wrote:
> > >> >> >
> > >> >> > Hello,
> > >> >> >
> > >> >> > (Sorry for the previous empty email - web page problem)
> > >> >> >
> > >> >> > please excuse another newbie question ...
> > >> >> >
> > >> >> > Ref: https://code.jsoftware.com/wiki/Vocabulary/starco
> > >> >> >
> > >> >> >    pythag =:  +&.*:
> > >> >> >    3 pythag 4
> > >> >> > 5
> > >> >> >
> > >> >> > + operated dyadically and acted on both x and y - ok.
> > >> >> >
> > >> >> > but how does *: know to act on x as well?  Isn't pythag using the
> > >> monadic
> > >> >> > definition of *: to square y only?
> > >> >> >
> > >> >> > so magical ...
> > >> >> >
> > >> >> > thank you for the pointer and have a great weekend.
> > >> >> >
> > >> >> >
> > >> >> > Maurice
> > >> >> >
> ----------------------------------------------------------------------
> > >> >> > For information about J forums see
> > >> http://www.jsoftware.com/forums.htm
> > >> >>
> > >> >>
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