Re: Octave's plotting much slower than matlab

[David Bateman]

Michael Goffioul wrote:
> On Jan 22, 2008 1:58 AM, David Bateman <address@hidden> wrote:
>   
>> 1) What should be done if the user gives NaN data in the patches?
>> Without matlab to check, I believe scatter should drop these points,
>> though I suppose they might be stored in the handle and dropped at the
>> time of plotting.
>>     
>
> Matlab seems to drop the NaN points in scatter. The resulting scatterseries
> object does not contain the NaN points (if I use 11 points [including 1 NaN],
> the scatterseries object has 10 patch children). BTW, I find the Matlab
> implementation quite inefficient: 1 point == 1 patch. Maybe we should use
> 1 patch for all points; as long as we provide a compatible scatterseries 
> object.
>
> As a side note, I see in __patch__.m that you're doing XY <-> Face/Vertex
> conversion. Maybe this should be moved to the C++ code, because this
> kind of conversion will be needed anyway, to update the patch object when
> the user changes something.
>
>   
>> 2) Can we vectorize the for-loop and at least get reasonable speed for
>> scatter with a SVN head version of JHandles? I think we can, but the
>> only means I saw to do it is quite messy. See the attached patch.
>>     
>
> I tried your patch and the improvement is huge:
>
> octave.exe:7> tic, scatter(rand(1,1000),rand(1,1000)), toc
> Elapsed time is 0.541099 seconds.
> octave.exe:8> close
> octave.exe:9> tic, scatter(rand(1,10000),rand(1,10000)), toc
> Elapsed time is 0.622619 seconds.
> octave.exe:10> close
> octave.exe:15> tic, scatter(rand(1,100000),rand(1,100000)), toc
> Elapsed time is 0.972446 seconds.
>
> I could not use 300k points, because Java ran out of memory
> (I could increase it, but I didn't try).
>
> Michael.
>
>   
Then we can apply this patch..

D.

-- 
David Bateman                                address@hidden
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