The following verbs appear to do what you want. --Kip Murray
plus =: [: (% +./) (+/ .* |.) , *&{:
neg =: -@{. , {:
minus =: plus neg
times =: [: (% +./) *
recip =: |.
divide =: times recip
On Sunday, March 6, 2016, Louis de Forcrand <[email protected]> wrote:
> I believe yours works if 1r2 + 3r4 would be written as 1 3 +pm 2 4.
> I would add:
> pm=: 1 : '(,&{. (% +./)@((u/@:* |.) , */@]) ,&{:)"1'
>
> Louis
>
> > On 06 Mar 2016, at 18:55, Pascal Jasmin <[email protected]
> <javascript:;>> wrote:
> >
> > an alternate pm
> >
> > pm =: 1 : '(% +./)@((u/@:* |.) , */@])"1'
> >
> >
> >
> > ________________________________
> > From: Louis de Forcrand <[email protected] <javascript:;> <mailto:
> [email protected] <javascript:;>>>
> > To: [email protected] <javascript:;> <mailto:
> [email protected] <javascript:;>>
> > Sent: Sunday, March 6, 2016 12:31 PM
> > Subject: [Jprogramming] Fractions challenge
> >
> >
> > Try to write a verb or adverb(s) that can add, subtract, multiply, and
> divide
> > two vectors of shape two which represent two exact fractions:
> >
> > 1 2 plus 3 4
> > 5 4
> > 1 2 minus 3 4
> > _1 4
> > 1 2 times 3 4
> > 3 8
> > 1 2 divide 3 4
> > 2 3
> >
> > At first sight this may seem useless, as exact arithmetic is already
> implemented,
> > but the idea is to have your function work with complex numbers as well:
> >
> > 0j1 1j2 plus 0j1 2j1
> > _3j3 0j5
> > 0j1 1j2 minus 0j1 2j1
> > 1j1 0j5
> > 0j1 1j2 times 0j1 2j1
> > _1 0j5
> > 0j1 1j2 divide 0j1 2j1
> > 9.0072e15 7.20576e15j5.40432e15 NB. “exact” ; if you ask J to do the
> division,
> > the result is correctly rounded off.
> >
> > 2 x: 2.5 3 3.5 ,: 4 4.5j2.5 5
> > |domain error
> > | 2 x:2.5 3 3.5,:4 4.5j2.5 5
> > frc 2.5 3 3.5 ,: 4 4.5j2.5 5 NB. convert to fractions
> > 5 2
> > 3 1
> > 7 2
> >
> > 4 1
> > 7j_2 1j_1
> > 5 1
> >
> > The fractions need to be simplified (so the numerator and denominator are
> > relatively prime), so I would suggest first finding how to simplify them
> > (that shouldn’t be too hard). If you feel like it, you can write two
> other verbs
> > to convert between fraction vector and decimal representation as well.
> >
> > Mine (two adverbs and two verbs; +/- and */%, plus conversion &
> simplification):
> >
> > pm=: 1 : '(% +./)@(*&{: ,~ ,&{. u/@:* ,~&{:)"1' NB. Plus Minus ->
> m +pm n
> > td=: 1 : '(% +./)@:u"1’ NB. Times Divide -> m *td n
> > simp=: (% +./)"1 NB. SIMPlify fractions
> > dec=: %/"1 :.((* (% +./)@,"0 ]) (>:@- >.)) NB. convert to
> DECimal/fraction
> >
> >
> > PS: On http://www.jsoftware.com/mailman/listinfo/programming <
> http://www.jsoftware.com/mailman/listinfo/programming> <
> http://www.jsoftware.com/mailman/listinfo/programming <
> http://www.jsoftware.com/mailman/listinfo/programming>> it says to send
> > messages to [email protected] <javascript:;> <mailto:
> [email protected] <javascript:;>> <mailto:
> [email protected] <javascript:;> <mailto:
> [email protected] <javascript:;>>>. Shouldn’t this be
> simply
> > [email protected] <javascript:;> <mailto:
> [email protected] <javascript:;>> <mailto:
> [email protected] <javascript:;> <mailto:[email protected]
> <javascript:;>>>?
> >
> > Good luck,
> > Louis
> > ----------------------------------------------------------------------
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> http://www.jsoftware.com/forums.htm>
> > ----------------------------------------------------------------------
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> http://www.jsoftware.com/forums.htm>
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