Update on my "bug report" -
H=: %@>:@(+/~)@i.
6!:2 '%. H 100x'
444.125
Not too shabby! And no crash. In the previous instance, I let the machine go
into sleep, so it may have been some snag about having a long running process
when iOS was trying to calm the machine...
On 2012/05/11 20:49 , Joey K Tuttle wrote:
> Yes, originally I used a 50 50 matrix. I've been looking for where I
> recorded timings for various older machines. So if you find them first,
> please send them along.
>
> My memory, increasingly faulty, is that 50 50 took about 7 seconds on
> the 360/50 (with a total of 256 Kbytes of RAM!), but that may have been
> the time on the Philadelphia 360/75 much faster with a huge 1 Mbyte
> RAM... This machine routinely supported 100+ users with 80 Kbyte workspaces.
>
> Another bit of related trivia is that the Philadelphia 75 was a return
> from NASA and the 60s space program. Also that Dick Lathwell had the
> console panel from it for years, I think he donated it to a museum,
> perhaps at Waterloo.
>
> For comparison, I just did the 50 50 on my iPad and it takes 0.00956 seconds
>
> Thanks for the reminders - your Hilbert one gives me the first chance to
> report a crash of J on the iPad.
>
> I tried it on my iMac
>
> H=: %@>:@(+/~)@i.
> 6!:2 '%. H 100x'
> 80.0178
>
> and then on the iPad - but after a few minutes, the app crashed, hard to
> say what happened, not likely a memory issue since it takes considerably
> less space than 500 500 ?@$ 1000
>
> On 2012/05/11 20:07 , Roger Hui wrote:
>> Somewhere I have recorded the times for the "JKT benchmark" on various
>> machines over the years. But didn't you used to use 50 50 matrices?
>> http://www.jsoftware.com/pipermail/programming/2007-December/009015.html
>>
>> Your report brings to mind two anecdotes concerning APL and matrix
>> inverses. The first concerns Ken's doctoral thesis work, for which he
>> solved some matrices for Leontief's input-output analysis. I've forgotten
>> the size of the matrices involved; it was something like 50 by 50 and was
>> on the Mark IV. Ken must have been an ace programmer. The Mark IV had a
>> 200 word memory (?).
>>
>> The second anecdote is this:
>> http://www.jsoftware.com/papers/APLQA.htm#Hilbert_matrix .
>>
>>
>>
>> On Fri, May 11, 2012 at 6:38 PM, Joey K Tuttle<[email protected]> wrote:
>>
>>> Wow! Is a response I've made several times about this new version of j.
>>> Marvelous that such a powerful application is so compact.
>>>
>>> Since I couldn't resist, one of the first expressions I entered on my
>>> iPhone 4 (not the faster 4s) was -
>>>
>>> 6!:2 '%. 500 500 ?@$ 1000'
>>> 18.2
>>>
>>> Amazing!
>>>
>>> The graphs on the iPhone retina are beautiful. I need strong glasses to
>>> hold it close enough to appreciate them and then the small font is OK too.
>>> My iPad is a 2 and now I wish for the retina display there too (not to
>>> mention the faster processor) - the inverse runs in 4.57 seconds on the
>>> iPad 2, also amazing.
>>>
>>> - joey iPa...
>>>
>>> On May 11, 2012, at 8:27, John Baker<[email protected]> wrote:
>>>
>>>> First impressions - wow!
>>>>
>>>> I ran through the install process on plain old 3g connections - no
>>> problems.
>>>> The app comes up . I was able to step through the initial demos without
>>>> problems. The standard J graphics
>>>> look great on the iPhone 4.
>>>>
>>>> Is there anyway to change the size of the default session font? The
>>>> current size is bit tiny for my old fart eyes.
>>>>
>>>> --
>>>> John D. Baker
>>>> [email protected]
>>>>
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>
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