In addition, I don't understand why
f=: (1:)`(* [: $: <:) @. *
shouldn't suffice, compared to
f=: (1:)`(] * [: $: <:) @. *
as
(* [: $: <:) y
looks to me like a regular hook.
-M
At 2023-05-25 18:33, you wrote:
This is odd.
According to https://code.jsoftware.com/wiki/Vocabulary/atdot f should
have rank 0 (since v is * here).
But, when I redefine f as
f=: 1:`(] * [: $:&([echo) <:)@.*
I see that when (f 2 3 5 7 11) is executed, f is being treated as some
other rank. This does not occur for (f 2 3 5 7).
Using $:@<: works around this issue by using $: with the rank of <:
(the rank problem with @. would still occur, without triggering a rank
error).
Also, the j implementation tells me that f has infinite rank - despite
what nuvoc says and despite the behavior for (f 2 3 5 7):
f b.0
_ _ _
--
Raul
On Thu, May 25, 2023 at 11:12â¯AM Martin Kreuzer <i...@airkreuzer.com> wrote:
> Dear all -
> Thought I had succeeded in deducing step by
step the tacit verb for factorial,
> f=: 1:`(] * [: $: <:)@.*
> when I encountered this:
> f=. 1:`(] * [: $: <:)@.*
> f 2 3 5 7
> 2 6 120 5040
> f 2 3 5 7 11
> |rank error in f, executing monad $:
> | f 2 3 5 7 11
> In contrast this seems to work alright:
> g=. 1:`(] * $: @ <:)@.* NB. dictionary entry
> g 2 3 5 7
> 2 6 120 5040
> g 2 3 5 7 11
> 2 6 120 5040 39916800
> JVERSION
> Engine: j9.4.2/j64avx2/windows
> Build: commercial/2023-04-10T01:19:53/clang-15-0-7/SLEEF=1
> Library: 9.4.21
> Platform: Win 64
> Installer: j9.4 install
> InstallPath: d:/program files (non-sys)/j9.4
> Contact: www.jsoftware.com
> However, my verb
> f=: 1:`(] * [: $: <:)@.*
> f 2 3 5 7 11 13
> 2 6 120 5040 39916800 6227020800
> works under v8.07 as expected ....
> Could somebody shed some light on this ?
> -M
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