[Insight-developers] fill

[Bill Lorensen]

What do the timings look like for small array size, e.g. 3, 4... ITK uses
Fill() to initialize sizes, indexes, points, etc. which are small.



On Wed, Apr 10, 2013 at 12:07 PM, Bradley Lowekamp
<blowekamp at mail.nih.gov>wrote:

> I was able to get quite similar numbers on RH w/ gcc 4.4.7 in standard
> release mode:
>
> Array size = 100, repetitions = 20000000
> The elapsed time for a C++ fill_n 690000 ms.
> The elapsed time for a itk.Fill   1910000 ms.
> The elapsed time for a C   fill   2620000 ms.
>
> Array size = 1000, repetitions = 2000000
> The elapsed time for a C++ fill_n 460000 ms.
> The elapsed time for a itk.Fill   1700000 ms.
> The elapsed time for a C   fill   2520000 ms.
>
> Array size = 10000, repetitions = 200000
> The elapsed time for a C++ fill_n 420000 ms.
> The elapsed time for a itk.Fill   1680000 ms.
> The elapsed time for a C   fill   2510000 ms.
>
> Array size = 100000, repetitions = 20000
> The elapsed time for a C++ fill_n 570000 ms.
> The elapsed time for a itk.Fill   1670000 ms.
> The elapsed time for a C   fill   2510000 ms.
>
> Array size = 1000000, repetitions = 2000
> The elapsed time for a C++ fill_n 600000 ms.
> The elapsed time for a itk.Fill   1680000 ms.
> The elapsed time for a C   fill   2510000 ms.
>
> Array size = 10000000, repetitions = 200
> The elapsed time for a C++ fill_n 1510000 ms.
> The elapsed time for a itk.Fill   1820000 ms.
> The elapsed time for a C   fill   2540000 ms.
>
> I did modify the test to set the value to 3.14, instead of 0, because
> other optimization may happen with a zero value...
>
> Brad
>
> On Apr 10, 2013, at 11:33 AM, Bill Lorensen <bill.lorensen at gmail.com>
> wrote:
>
> Or maybe Ubuntu is milliseconds and windows is seconds?
>
>
>
> On Wed, Apr 10, 2013 at 11:28 AM, Bill Lorensen <bill.lorensen at gmail.com>wrote:
>
>> The Ubuntu timings are much longer than windows. Was that expected?
>>
>>
>>
>> On Wed, Apr 10, 2013 at 10:42 AM, <M.Staring at lumc.nl> wrote:
>>
>>>
>>>
>>> -----Original Message-----
>>> From: Staring, M. (LKEB)
>>> Sent: woensdag 10 april 2013 16:28
>>> To: Insight Developers (insight-developers at itk.org)
>>> Subject: FW: fill
>>>
>>> Forgot to include the maliing list
>>>
>>> -----Original Message-----
>>> From: Staring, M. (LKEB)
>>> Sent: woensdag 10 april 2013 16:24
>>> To: 'Williams, Norman K'; blowekamp at mail.nih.gov
>>> Cc: matt.mccormick at kitware.com
>>> Subject: RE: fill
>>>
>>> Hi,
>>>
>>> Attached you can find some timings for different POD types, I tested for
>>> short, int, float and double. std::fill_n is always faster, but less so for
>>> longer types.
>>>
>>> I simply modified itk::Array::Fill to use std::fill_n instead of
>>> referring to the vnl_vector::fill which uses a simple loop over the data.
>>> Not sure if this is the way to go, but my experimental looks green:
>>>
>>>         http://open.cdash.org/buildSummary.php?buildid=2871413
>>>
>>> The patch I just submitted to gerrit:
>>>
>>>         http://review.source.kitware.com/#/c/10801/
>>>
>>> Curious to your comments,
>>>
>>> Regards, Marius
>>>
>>> -----Original Message-----
>>>
>>>
>>> _______________________________________________
>>> Powered by www.kitware.com
>>>
>>> Visit other Kitware open-source projects at
>>> http://www.kitware.com/opensource/opensource.html
>>>
>>> Kitware offers ITK Training Courses, for more information visit:
>>> http://kitware.com/products/protraining.php
>>>
>>> Please keep messages on-topic and check the ITK FAQ at:
>>> http://www.itk.org/Wiki/ITK_FAQ
>>>
>>> Follow this link to subscribe/unsubscribe:
>>> http://www.itk.org/mailman/listinfo/insight-developers
>>>
>>>
>>
>>
>> --
>> Unpaid intern in BillsBasement at noware dot com
>>
>
>
>
> --
> Unpaid intern in BillsBasement at noware dot com
>  _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Kitware offers ITK Training Courses, for more information visit:
> http://kitware.com/products/protraining.php
>
> Please keep messages on-topic and check the ITK FAQ at:
> http://www.itk.org/Wiki/ITK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.itk.org/mailman/listinfo/insight-developers
>
>
>


-- 
Unpaid intern in BillsBasement at noware dot com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-developers/attachments/20130411/a59c2ffe/attachment.htm>