You can use the dot to combine other things though it's probably most
commonly used for matrix multiplication but it's a generalization of the
ideas underlying that:
>;:'This is a table of words'
This
is
a
table
of
words
(>;:'This is a table of words') *./ . = 'table'
0 0 0 1 0 0
$>;:'This is a table of words'
6 5
(>;:'This is a table of words') *./ . = 5{.'of'
0 0 0 0 1 0
(>;:'This is a table of words') *./ . = |:>'of';'table';'FOO'
0 0 0
0 0 0
0 0 0
0 1 0
1 0 0
0 0 0
And, of course, we also can extend matrix multiplication to higher
dimensions:
(i.2 3 4) +/ . * i.4
14 38 62
86 110 134
(i.2 3 4) +/ . * i.4 5
70 76 82 88 94
190 212 234 256 278
310 348 386 424 462
430 484 538 592 646
550 620 690 760 830
670 756 842 928 1014
On Thu, Jul 11, 2013 at 8:53 AM, Simon Barker <[email protected]>wrote:
> J's parsing shows symbol recognition nicely:
>
> .*
> +-+-+
> |.|*|
> +-+-+
> *.
> +--+
> |*.|
> +--+
> . *
> +-+-+
> |.|*|
> +-+-+
> * .
> +-+-+
> |*|.|
> +-+-+
>
> Searching archives by keyword:
>
> http://jsoftware.2058.n7.nabble.com/
>
> As described here:
>
> http://www.jsoftware.com/jwiki/System/Forums
>
> Simon
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Brian
> Schott
> Sent: 11 July 2013 13:38
> To: [email protected]
> Subject: Re: [Jprogramming] What is .*?
>
> (B0 13) +/ .* (i.!]) 13x
> I believe the code you are referring to is above. The phrase you are
> looking
> for is part of matrix multiplication. The dot is a separate symbol.
> ---
> (B=)
>
> On Jul 10, 2013, at 11:27 PM, Vijay Lulla <[email protected]> wrote:
>
> > Hi all,
> > Forgive me if this has been answered somewhere else previously.
> >
> > I was reading the essay on Bernoulli Numbers (
> > http://www.jsoftware.com/jwiki/Essays/Bernoulli%20Numbers) and came
> > across
> > .* (in the third code example block). I don't know what it does and I
> > couldn't find anything in either the vocabulary or parts of speech pages.
> > Any explanations/pointers are highly appreciated.
> >
> > On a side note, how do I search list archives for particular keyword
> > or topic?
> > Thanks in advance,
> > Vijay.
> > ----------------------------------------------------------------------
> > 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
>
--
Devon McCormick, CFA
^me^ at acm.
org is my
preferred e-mail
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
