<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Hi, Godofredo, I ran some timing tests on vtkdelaunay2D this morning
after your post and found that vtkDelaunay2D performance is actually
O(n^2) when compiled for debug. See
<a class="moz-txt-link-freetext" href="http://quaoar.sr.unh.edu/vtkDelaunay2D/">http://quaoar.sr.unh.edu/vtkDelaunay2D/</a> for the details. I am running a
linux box with the latest stable VTK. These results should give a
reference point to compare your VC++ build against. <br>
burlen<br>
<br>
Godofredo wrote:
<blockquote cite="mid:14581000.post@talk.nabble.com" type="cite">
<pre wrap="">Hi, I haven't tried it yet under another platform. Sure it's slow by itself
but I don't think that it should be that slow. Take a look at this
unanswered post (quite old) regarding to VC7 vs VC6 and vtkDelaunay2D:
<a class="moz-txt-link-freetext" href="http://public.kitware.com/pipermail/vtkusers/2002-December/064429.html">http://public.kitware.com/pipermail/vtkusers/2002-December/064429.html</a>
As soon I've time, I'll try under another platform to evaluate the algorithm
performance. Meanwhile any comment is wellcomed. Thanks to all.
santana wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi, Delaunay is slow algorithm in general, it has to work point by point
and make a search through the point set with each insertion. I am not
sure about VTK but I have seen the time complexity of other
implementations is O(n*log(n)). It sounds like you by hand approach is
O(n) so would be much faster. You mentioned that you think it is related
to VC++ 2005 but I think it is the delaunay algorithm itself rather than
the platform which is the problem. have you tried under another platform?
Burlen
Godofredo wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi to all, I've been doing some triangulations with big datasets and
found
out that vtkDelaunay2D is extremely slow in VC++ 2005. I've done the
triangulation by hand (as my data came from a range scanner I just join
the
verts in order) and It takes only seconds to triangulate what with
vtkDelaunay2D takes almost 2 minutes. I've found in the forums a post
that
talked about the same problem but had no replys. Anyone could put some
light
into this? Many thanks.
</pre>
</blockquote>
<pre wrap="">_______________________________________________
This is the private VTK discussion list.
Please keep messages on-topic. Check the FAQ at:
<a class="moz-txt-link-freetext" href="http://www.vtk.org/Wiki/VTK_FAQ">http://www.vtk.org/Wiki/VTK_FAQ</a>
Follow this link to subscribe/unsubscribe:
<a class="moz-txt-link-freetext" href="http://www.vtk.org/mailman/listinfo/vtkusers">http://www.vtk.org/mailman/listinfo/vtkusers</a>
-----
<a class="moz-txt-link-freetext" href="http://quaoar.sr.unh.edu">http://quaoar.sr.unh.edu</a>
</pre>
</blockquote>
<pre wrap=""><!---->
</pre>
</blockquote>
<br>
</body>
</html>