Just back from doing a BBC Prom! Very loud... Still some
voice left.
If I'm doing a simulation, I often do ? on a large sample,
eg ?1000000#1000 or the like, and then "draw" from that
sample in sequence. Usually for independent trials.
For example, for this donation problem, it _might_ be
preferable to sample ?10000 400$400 and then work down
the 10000 rows than doing the ^:10000 trick. (The trials
are still independent, assuming you're happy to sample
even for the non-donors.)
I haven't tried that approach here, so don't know off hand
whether it's worth trying.
Cheers,
Mike
On 27/07/2017 21:27, Jimmy Gauvin wrote:
I was wondering if making rg tacit would boost performance.
Thanks to Raul for answering my unvoiced question.
I guess key, nub and amend are well optimized in the J interpreter.
Jimmy
PS Is roll also optimized for speed? If not should we look into ISAAC or
other fast PRNGs?
On Thu, Jul 27, 2017 at 5:23 AM, Raul Miller <rauldmil...@gmail.com> wrote:
Ah, i was testing it on too small of a data set.
Thanks,
--
Raul
On Thu, Jul 27, 2017 at 4:33 AM, 'Mike Day' via Programming
<programm...@jsoftware.com> wrote:
Jimmy's original rg outperforms both tock and the best of
my various attempts at "new" for "larger" problems, eg
10 ts 'rg^:10000 #~400'
0.633403 38272
10 ts 'tock^:10000 #~400'
0.751826 34816
10 ts 'new^:10000 #~400'
0.793394 39424
NB. less good on smaller ones
30 ts 'rg^:10000 #~10'
0.10968 6784
30 ts 'tock^:10000 #~10'
0.0662844 3840
30 ts 'new^:10000 #~10'
0.0633482 3968
(Have you looked at Raul's results table, posted on 20/7?)
The original problem asked us to consider 100 players,
but, as usual, it's one thing to solve a small puzzle that you
can get your head round, but very often a much more challenging
requirement to get it to scale up.
Those many Project Euler problems are worth looking at with
scale of application in mind. ( //projecteuler.net )
Thanks,
Mike
On 27/07/2017 05:54, Raul Miller wrote:
Oh, well, you could make it tacit. For example:
rg=:(((#/.~@])`(~.@])`(0*[)} +/?@##)+-) *
That does not speed it up, though.
Anyways, good luck,
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