I updated the page with dyad ts,
on AMD processor, j7-64, I still get a significant speedup on a3 over a2 lines.
100 ts '(i.50000) { a2'
232.455/sec 4.72026MB
100 ts '(i.50000) { L:0 a3'
558.897/sec 5.76986MB
----- Original Message -----
From: Devon McCormick <[email protected]>
To: J-programming forum <[email protected]>
Cc:
Sent: Thursday, September 12, 2013 5:39:23 PM
Subject: Re: [Jprogramming] An essay on boxed vs unboxed table performance
Not sure how useful these timings are as they differ substantially from
what I see on
JVERSION
Engine: j701/2011-01-10/11:25
Library: 7.01.083
Platform: Win 64
Installer: j701a_win64.exe
InstallPath: c:/program files (x86)/j64-701
That is, for the second set, I see no significant difference versus what
looks like a substantial difference on the wiki article:
(100) 6!:2 '(i.50000) { a2'
0.00237792
(100) 6!:2 '(i.50000) { L:0 a3'
0.00226677
On Thu, Sep 12, 2013 at 5:28 PM, Devon McCormick <[email protected]> wrote:
> This is one reason I like to look at time separately from space as 6!:2
> takes an optional left argument to average the timing over multiple
> repetitions, e.g.
>
>
> 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.00741604
> 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.00668613
> 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.00724116
> 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.00575015
> 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.00510153
>
> NB. Fairly high variance above vs. below:
>
> (10) 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.00504947
> (10) 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.004953
> (10) 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.0048413
> (10) 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.0046273
> (10) 6!:2 '0 1{"1 ] 100000 10 $ a'
> 0.00477414
>
>
>
> On Thu, Sep 12, 2013 at 4:29 PM, Raul Miller <[email protected]>wrote:
>
>> I would note that several things can significantly influence timings.
>> It's also probably not wise to assuming that timing numbers are
>> completely reproducible.
>>
>> ts '0 1{"1 ] 100000 10 $ a'
>> 0.005122 1.04882e7
>> ts '0 1{"1 ] 100000 10 $ a'
>> 0.00191 1.04882e7
>> ts '0 1{"1 ] 100000 10 $ a'
>> 0.00194 1.04882e7
>>
>> Things that can influence timing include the version of the
>> interpreter, the make of the cpu and the amount of available memory
>> (compared to what's being used in the timing). Here, though, we're
>> only using 10MB for intermediate results, which is relatively small on
>> typical current computers.
>>
>> Thanks,
>>
>> --
>> Raul
>>
>> On Thu, Sep 12, 2013 at 3:35 PM, Pascal Jasmin <[email protected]>
>> wrote:
>> >
>> >
>> > An essay on boxed vs unboxed table data.
>> http://www.jsoftware.com/jwiki/PascalJasmin/Boxed%20vs%20unboxed%20data .
>> >
>> > The results might surprise most of you since there's been signficant
>> performance tuning in J (around boxing) since its earlier days, and jmf and
>> 3!:1 supports boxed data too now.
>> >
>> > Let me know if I've made mistakes, or overlooked something big.
>> > ----------------------------------------------------------------------
>> > 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
>
>
--
Devon McCormick, CFA
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