with nesting, I'm not sure of the equivalency 3 (2&(+&2@]^:[))^:[ 3
39 3 (2&(+&2)) 3 15 but the actual equivalent is 3 (2&(+&2@]^:[)@:])^:[ 3 15 +&2^:6 ] 3 15 +&2^:(18) ] 3 39 I'm not sure why the first is 39, but I understood why the short expression/last 2 was 15. But a short "verbification of power" P =: (@])(^:[) 2 +&2 P 3 7 (3) 2&(2&+ P) P 3 15 On Monday, August 17, 2020, 11:29:48 a.m. EDT, Henry Rich <henryhr...@gmail.com> wrote: Now that I think of it, x m&v y is equivalent to x (m&v @ ] ^: [) y so there is never going to be a case where dyadic m&v is necessary. The question is how valuable the uses mentioned are. I know I have lost a lot of time over the years by mistaken execution of dyadic m&v, and a domain error would have served me better. Henry Rich On 8/17/2020 10:57 AM, 'Pascal Jasmin' via Programming wrote: > Tetration (I think it is called) is an impressive display of dyadic (m&) > > You are allowed to keep adding (&m) bindings. > > As a hybrid depth/breadth first (do depth 10 times in a breadth way), then > > 10 x&search^:(until)^:_ y > > lets you make that chunk size a verb parameter. > > > With that said, there is surely a way to box x, and extract items from it on > the v side of ^:, but then you need to include a 1 result in the relevant x > position and set a maximum possible "exponentiation/tetration" level. > > While I certainly admit that in the life of a J programmer, you will more > often accidentally call a bound (&) verb dyadically on accident rather than > on purpose, which often results in infinitish loop hang/delays, it hasn't > happened to me in a while, so I'm somehow hopeful that it this construct > could still be more useful than my future accidents probabilities. > > > On Monday, August 17, 2020, 10:21:05 a.m. EDT, Henry Rich > <henryhr...@gmail.com> wrote: > > > > > > On the current implementation it is much preferable to use > > bitmask operator@]^:["0 operand > > rather than > > bitmask 0&(] operator)"0 operand > > They both execute at low rank, but the second version reinterprets the > internal form ( 0&(] operator)^:bitmask ) for each atom. > > > > I have yet to find an application where (x m&v y) is needed. Does anyone > have one? In the example above, the 0& could be any value and is used > only as a way of getting the power function. > > > Henry Rich > > > > > On 8/17/2020 9:30 AM, David Lambert wrote: >> Yes, thank you Roger for this explanation of dyadic & which i've recently >> been thinking about how to incorporate into my j programming. >> >> |Date: Sun, 16 Aug 2020 21:00:42 +0000 (UTC) >> |From: "'Pascal Jasmin' via Programming" <programm...@jsoftware.com> >> |To: "programm...@jsoftware.com" <programm...@jsoftware.com> >> |Subject: Re: [Jprogramming] conditional application defined by bitmask >> |Message-ID: <316224114.2834748.1597611642...@mail.yahoo.com> >> |Content-Type: text/plain; charset=UTF-8 >> | >> |Roger's solution includes an intermediate-advanced J concept I knew about, >> and an advanced realization I did not previously realize/know about. >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm > -- This email has been checked for viruses by AVG. https://www.avg.com ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
