Hi Jose.
No sir! I have not considered that generalization of the verb 'simplify'. I 
will look into it. 
(I must remember to use double enter in order that the mail program does not 
mess up my mail.)
(k simplify n)  has the same k moments as vector  n.
Examples of simplify:
   simplify
4 : 0
y=.x*}.(%{.)+/y^/i.>:x
x=.1
for.y do.x=.((-/x*(#x){.y)%#x),x end.
-|.>{:p.x
) 
   ]n=.?8#0 NB. test data
0.17212 0.51129 0.190085 0.752359 0.223673 0.177596 0.730671 0.766152

 1 simplify n NB. mean value
0.440493 

 2 simplify n NB. mean plusminus std.dev.
0.179873 0.701114

 3 simplify n
0.138829 0.407932 0.774719

 (3 & simplify &. (10&+)) n NB. adding a constant 
0.138829 0.407932 0.774719


 (3 & simplify &. (10&*)) n NB. multiply by constant
0.138829 0.407932 0.774719


 2 simplify 3 simplify n NB. further simplifying
0.179873 0.701114

1 simplify 2 simplify n NB. further simplifying
0.440493

Thanks! Bo.
 

    Den 21:16 søndag den 17. juli 2016 skrev Jose Mario Quintana 
<jose.mario.quint...@gmail.com>:
 
 

 Hi Bo,

The particular monadic case 2&simplify, as I understand it, produces a
vector (of size two) which has the same two moments as the original vector
(e.g., if the argument  Y  is a vector of univariate observations, for
instance the heights of a group of  N  people then the product of
 2&simplify Y  would be a vector Z  of two "heights" which would have the
same mean and variance as  Y ).

Now, assume one also has the weights of the same group of people and the
bivariate observations  Y  contains now their heights and weights collected
as a matrix with  N  rows and two columns (height and weight).  The problem
is: find another matrix  Z  of "heights and weights" with a minimum number
 M  of rows (M <: N) such that the (1x2) mean vector and the (2x2)
variance-covariance matrix  of Z are the same as the mean and
variance-covariance matrix of  Y .  More generally, what would be the
corresponding Z for multivariate observations?  (I guess the number of rows
 M  , apart from rounding, should depend linearly on the number of columns
of the multivariate observations.)

I was just wondering if you had consider that kind of problems.



On Fri, Jun 26, 2015 at 3:50 AM, 'Bo Jacoby' via Programming <
programm...@jsoftware.com> wrote:

> Explanation: The vector 'A simplify B' has the same A moments as the
> vector B.Examples:  1 simplify 0 21  2 simplify 0 20 2  3 simplify 0
> 2_0.224745 1 2.22474  2 simplify 3 simplify 0 20 2  1 simplify 3 simplify
> 0 21
>
>
>
>
>      Den 0:04 fredag den 26. juni 2015 skrev Kip Murray <
> thekipmur...@gmail.com>:
>
>
>
>  1 X
>
>  2 X X
>
>  3
>
>  4 X
>
>  5
>
>  6 X
>
>
>  1 X
>
>  2
>
>  3 X
>
>  4
>
>  5 X
>
>  6
>
>
>  1
>    X
>  2 X
>
>  3
>
>  4
>
>  5 X
>
>  6
>
>
> Above I have attempted three histograms.  The first shows the data set 1 2
> 2 4 6 which has mean 3 and standard deviation 2, median 2 and fourths (not
> quartiles) 1.5 and 5 .  The second histogram shows the mean and the mean
> plus or minus a standard deviation, and the third histogram shows the
> median and fourths.  (The fourths are respectively the median of the
> numbers below the median, and the median of the numbers above the median.)
>
> --Kip Murray
>
>
> On Thursday, June 25, 2015, Devon McCormick <devon...@gmail.com> wrote:
>
> > I put together this J based on the "fivenum" routine in R mentioned in
> the
> > Wikipedia link:
> >
> > fivenum=: 3 : 0
> >    if. 0=#y=. /:~y do. 5#_.
> >    else. n4=. -:<.-:3+#y
> >        d=. <:1,n4,(-:>:#y),(n4-~>:#y),#y
> >        -:(y{~<.d)+y{~>.d
> >    end.
> > )
> >
> > It returns the minimum, the quartile points, and the maximum of a series.
> > The first branch of the "if" roughly replicates some of the R function's
> > NA-handling.
> >
> > On Thu, Jun 25, 2015 at 10:14 AM, David Lambert <b49p23t...@gmail.com
> > <javascript:;>>
> > wrote:
> >
> > > Is simplify supposed to report the i.x moments of the data?  Would be
> > > useful.
> > > When I removed the question marks from simplify to make valid j
> > >    1 simplify DATA NB. does report the mean
> > > Otherwise I haven't made sense of the results for the verb I created.
> > >
> > >    datatype N
> > > integer
> > >
> > >    3 simplify N
> > > _951.236j1533.8 _951.236j_1533.8 2658.39
> > >
> > >  Date: Thu, 25 Jun 2015 08:39:51 +0000 (UTC)
> > >> From: "'Bo Jacoby' via Programming"<programm...@jsoftware.com
> > <javascript:;>>
> > >> To: Programming Forum<programm...@jsoftware.com <javascript:;>>
> > >> Subject: [Jprogramming] simplify
> > >> Message-ID:
> > >>        <
> 1806252176.1379402.1435221591208.javamail.ya...@mail.yahoo.com
> > <javascript:;>>
> > >> Content-Type: text/plain; charset=UTF-8
> > >>
> > >> NB.?If you have got a bunch of numbers? ? ? ]n=.?20#10035 32 66 37 94
> 56
> > >> 44 30 25 70 27 68 49 92 96 79 74 99 72 22NB. and you want to simplify,
> > then
> > >> take the mean value
> > >>
> > >
> > >  <unreadable cut>
> > >>
> > >
> > >  )NB.?If you can simplify the programming, the please let me know.
> > >> ThanksBo
> > >>
> > >
> > > ----------------------------------------------------------------------
> > > For information about J forums see http://www.jsoftware.com/forums.htm
> > >
> >
> >
> >
> > --
> > Devon McCormick, CFA
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> >
>
>
> --
> Sent from Gmail Mobile
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
>
>
>
> ----------------------------------------------------------------------
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