After reading this thread from September, I couldn't resist an "elementary
school" version, shown twice below:
f=: 13 :'>:?y$6'
]A=:f 20 NB. Original rolls
5 1 4 1 5 2 2 6 2 4 5 6 1 3 6 2 1 4 4 2
}:1,6~:A
1 1 1 1 1 1 1 1 0 1 1 1 0 1 1 0 1 1 1 1
]B=:(}:1,6~:A)<;.1 A NB. Boxes show extra rolls
--T-T-T-T-T-T-T---T-T-T---T-T---T-T-T-T-┐
│5│1│4│1│5│2│2│6 2│4│5│6 1│3│6 2│1│4│4│2│
L-+-+-+-+-+-+-+---+-+-+---+-+---+-+-+-+--
]C=:+/"1 >B NB. Value of rolls
5 1 4 1 5 2 2 8 4 5 7 3 8 1 4 4 2
$C NB. Usable answers
17
f=: 13 :'>:?y$6'
]A=:f 20 NB. Original rolls
1 2 6 6 6 5 3 5 1 6 6 3 1 4 2 6 4 1 2 2
}:1,6~:A
1 1 1 0 0 0 1 1 1 1 0 0 1 1 1 1 0 1 1 1
]B=:(}:1,6~:A)<;.1 A NB. Boxes show extra rolls
--T-T-------T-T-T-T-----T-T-T-T---T-T-T-┐
│1│2│6 6 6 5│3│5│1│6 6 3│1│4│2│6 4│1│2│2│
L-+-+-------+-+-+-+-----+-+-+-+---+-+-+--
]C=:+/"1 >B NB. Value of rolls
1 2 23 3 5 1 15 1 4 2 10 1 2 2
$C NB. Usable answers
14
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Raul Miller
Sent: Friday, September 26, 2014 11:50 PM
To: Programming forum
Subject: Re: [Jprogramming] Repeated rolling dice
In addition to Pascal's comments, "0 can sometimes run into an issue with
word formation rules (when the argument to the right begins with a number).
Thanks,
--
Raul
On Fri, Sep 26, 2014 at 12:05 PM, Johann Hibschman <
<mailto:[email protected]> [email protected]>
wrote:
> Thanks, that's helpful, although the tacit version of "bulk" is a bit
> too much for me to parse.
>
> I imagine factor of 2 helps because it gets you over the expected 6r5
> rolls per "game", assuming I did that recurrence right
> (e=(5r6*1)+1r6*(1+e)).
>
> I do have some lingering style questions though:
>
> 1. It looks to me like David Lambert's solution used both (&>) and
> (">) to force a verb to apply to the atoms, which I would write ("0).
> Are there any particular reasons to prefer one over the other? ("0)
> may require a ([) to avoid merging with a follow-up literal, (&>)
> seems a little like exploiting a side-effect of (>), and (">) could
> just as easily be ("+) or any other 0 0 0 verb.
>
> 2. Is there any difference between (bind) and (@:)? They look to me
> like they would be identical.
>
> Thanks,
> Johann
>
> On Thu, Sep 25, 2014 at 3:10 PM, Raul Miller <
<mailto:[email protected]> [email protected]>
> wrote:
> > That is very close to what I came up with, for the case where we
> > want
> only
> > a single value from our result:
> >
> > d6=:1 + ? bind 6
> > repd6=: [:+/(,d6)^:(6={:)@d6
> >
> > Here's a variation on Roger Hui's approach, for the case where we
> > want N values from our result:
> >
> > d6s=: 1 + [: ? #&6
> > bulk=:{.#&0(],~(+/;.1~1:}:@,0~:6&|)@(],d6s@[))^:(
<mailto:0=6&;|@%7b:@%7b.)%5e:_~> 0=6&|@{:@{.)^:_~]
> >
> > Example use:
> > bulk 20
> > 5 5 5 4 3 3 2 3 3 9 1 4 16 3 3 1 3 17 3 4
> >
> > This would probably be much clearer if implemented explicitly rather
> > than tacitly, and probably would be more efficient also. So:
> >
> > bulkd6s=:3 :0
> > r=. i. 0
> > while. y >: #r do.
> > r=. r, d6s y
> > mask=. }: 1, 0~:6|r
> > r=. mask +/;.1 r
> > end.
> > y{.r
> > )
> >
> > But statistically speaking, this is still not as efficient as it
> > could
> be.
> > I think we'd do better with:
> >
> > bulkd6=:3 :0
> > r=. i. 0
> > while. y >: #r do.
> > r=. r, d6s 2*y
> > mask=. }: 1, 0~:6|r
> > r=. mask +/;.1 r
> > end.
> > y{.r
> > )
> >
> > Do you see why this tends to be more efficient?
> >
> > Thanks,
> >
> > --
> > Raul
> >
> >
> > On Thu, Sep 25, 2014 at 11:50 AM, 'Pascal Jasmin' via Programming <
> > <mailto:[email protected]> [email protected]> wrote:
> >
> >> this works
> >>
> >> (, >:@?@6:)^:((0=#) +. 6={:)^:_ i.0
> >>
> >> ([: +/ (, >:@?@6:)^:((0=#) +. 6={:)^:_) i.0
> >> 11
> >>
> >>
> >>
> >> ----- Original Message -----
> >> From: Johann Hibschman < <mailto:[email protected]>
[email protected]>
> >> To: Programming forum < <mailto:[email protected]>
[email protected]>
> >> Cc:
> >> Sent: Thursday, September 25, 2014 9:06 AM
> >> Subject: [Jprogramming] Repeated rolling dice
> >>
> >> Hi all,
> >>
> >> For fun, I've been running some statistics for a game with an
> >> unusual rule for rolling dice: if a 6 is rolled, roll again and add
> >> the result, repeating on any subsequent 6s. I wanted to implement
> >> this in J, collecting all the individual rolls (rather than just
> >> the sum.)
> >>
> >> It seems like there should be a more clever and elegant way to do
> >> this, but this is what I have:
> >>
> >> NB. Simple roll.
> >> roll0 =: >:@?
> >>
> >> NB. This seems to work, but it's not very clever.
> >> roll =: 3 : 0
> >> r =. >:?y
> >> if. r=y do. r=. r,(roll y) end.
> >> r
> >> )
> >>
> >> NB. Attempt at iterating via power. Fails because repeats NB.
> >> signal termination.
> >> roll0^:(6&=)^:(<_) 6
> >>
> >> NB. Attempt at iterating via agenda. Not even close yet.
> >> NB. ]`(]+$:) @. (=&6) NB. where to stick in the roll?
> >>
> >> This gives what I expect:
> >>
> >> roll"0 ] 10#6
> >> 6 1 0
> >> 3 0 0
> >> 3 0 0
> >> 2 0 0
> >> 5 0 0
> >> 2 0 0
> >> 6 6 2
> >> 2 0 0
> >> 1 0 0
> >> 6 3 0
> >>
> >> But is there a better way to do this? Also, are there any known
> >> issues with the RNG? I've not gathered enough statistics to prove
> >> it, but the results look clumpier (more identical values in a row) than
I expect.
> >> Now, I know that's a common cognitive bias, so it may just be me,
> >> but is there a discussion of the quality of the RNG somewhere?
> >>
> >> Thanks,
> >> Johann
> >> -------------------------------------------------------------------
> >> --- For information about J forums see
> >> <http://www.jsoftware.com/forums.htm>
http://www.jsoftware.com/forums.htm
> >>
> >> -------------------------------------------------------------------
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> >> <http://www.jsoftware.com/forums.htm>
http://www.jsoftware.com/forums.htm
> >>
> > --------------------------------------------------------------------
> > -- For information about J forums see
> > <http://www.jsoftware.com/forums.htm>
http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see <http://www.jsoftware.com/forums.htm>
http://www.jsoftware.com/forums.htm
>
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