[vtk-developers] Fwd: A question regarding the most efficient way to merge neighbouring points in an iterative method

[Philippe Pébay]

Ah! Thanks for the very useful comparison, I am going to test with it as
well.

P.

On Mon, Mar 18, 2013 at 5:40 PM, Robert Maynard
<robert.maynard at kitware.com>wrote:

> Forgot to send this email to the mailing list.
>
>
> I have updated the point generator implementation to be more fair. The
> first pass was quickly done on the airplane, and caused the points to fall
> on a straight line in space causing some really bad octree behavior. Now I
> get the vector implementation being roughly 4 times faster.
>
>
> On Mon, Mar 18, 2013 at 2:15 AM, Philippe Pébay <
> philippe.pebay at kitware.com> wrote:
>
>> Sorry, I did not notice that the .h also contained the implementation.
>>
>> Thanks
>> P
>>
>>
>> On Mon, Mar 18, 2013 at 7:14 AM, Philippe Pébay <
>> philippe.pebay at kitware.com> wrote:
>>
>>> Thanks Robert, this is most useful. On the github web interfact I can
>>> only see the headers, how can I look at the implementation files?
>>>
>>> Thanks again
>>> P
>>>
>>>
>>> On Mon, Mar 18, 2013 at 7:08 AM, Robert Maynard <
>>> robert.maynard at kitware.com> wrote:
>>>
>>>> For DAX we have had good success with sort, unique and than lower
>>>> bounds to reduce a vector of points into the unique points.
>>>>
>>>> To can check out the benchmark code I wrote here:
>>>> https://github.com/robertmaynard/PointMergingBenchmark to try out
>>>> both an incremental octree point locator and the sort code.
>>>>
>>>> On 10 million points with 66% of them being duplicates under release
>>>> mode ( which is very important ), I get the lower bounds methods
>>>> being ~9 to 10 times faster.
>>>>
>>>>
>>>>
>>>>
>>>> On Sun, Mar 17, 2013 at 8:25 AM, Philippe Pébay <
>>>> philippe.pebay at kitware.com> wrote:
>>>>
>>>>> Hello all,
>>>>>
>>>>> I have a question regarding the most efficient way to insert points in
>>>>> an iterative method creating those as the algorithm progresses.
>>>>>
>>>>> Naively I am using a locator to insert each new point and possibly
>>>>> merge it on the fly if it is epsilon-close to a pre-existing one. This is
>>>>> convenient  and memory-wise this is efficient because the code does not
>>>>> grow a list of replicated points.
>>>>>
>>>>> However, if we put memory aside and focus on speed, then it seems to
>>>>> be more effective to merge points in a single pass, once they have all been
>>>>> created. Especially as the complexity of the mesh increases.
>>>>>
>>>>> If anyone has looked into this issue I would appreciate any elements
>>>>> of discussion.
>>>>>
>>>>> Thank you
>>>>> Philippe
>>>>>
>>>>> --
>>>>> Philippe Pébay, PhD
>>>>> Director of Visualization and High Performance Computing /
>>>>> Directeur de la Visualisation et du Calcul Haute Performance
>>>>> Kitware SAS
>>>>> 26 rue Louis Guérin, 69100 Villeurbanne, France
>>>>> +33 (0) 6.83.61.55.70 / 4.37.45.04.15
>>>>> http://www.kitware.fr <http://www.kitware.fr/>
>>>>> _______________________________________________
>>>>> Powered by www.kitware.com
>>>>>
>>>>> Visit other Kitware open-source projects at
>>>>> http://www.kitware.com/opensource/opensource.html
>>>>>
>>>>> Follow this link to subscribe/unsubscribe:
>>>>> http://www.vtk.org/mailman/listinfo/vtk-developers
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Robert Maynard
>>>>
>>>
>>>
>>>
>>> --
>>> Philippe Pébay, PhD
>>> Director of Visualization and High Performance Computing /
>>> Directeur de la Visualisation et du Calcul Haute Performance
>>> Kitware SAS
>>> 26 rue Louis Guérin, 69100 Villeurbanne, France
>>> +33 (0) 6.83.61.55.70 / 4.37.45.04.15
>>> http://www.kitware.fr <http://www.kitware.fr/>
>>>
>>
>>
>>
>> --
>> Philippe Pébay, PhD
>> Director of Visualization and High Performance Computing /
>> Directeur de la Visualisation et du Calcul Haute Performance
>> Kitware SAS
>> 26 rue Louis Guérin, 69100 Villeurbanne, France
>> +33 (0) 6.83.61.55.70 / 4.37.45.04.15
>> http://www.kitware.fr <http://www.kitware.fr/>
>>
>
>
>
> --
> Robert Maynard
>
>
>
> --
> Robert Maynard
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtk-developers
>
>
>


-- 
Philippe Pébay, PhD
Director of Visualization and High Performance Computing /
Directeur de la Visualisation et du Calcul Haute Performance
Kitware SAS
26 rue Louis Guérin, 69100 Villeurbanne, France
+33 (0) 6.83.61.55.70 / 4.37.45.04.15
http://www.kitware.fr <http://www.kitware.fr/>
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