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Thanks Zhanping. <br>
<br>
I'm not sure this answers the question of why it is crashing though, as
it only happens when the streamline output is connected to a contour
filter, and happens even when generating what appear to be valid
streamlines. I also did some testing, and the behavior appears to be
independent of whether Mask Points or something else (e.g.
SphereSource) is used for the seed points...<br>
<br>
David<br>
<br>
<br>
<br>
<br>
On 5/7/2010 1:23 PM, Zhanping Liu wrote:
<blockquote
cite="mid:m2yf8d97d9d1005071023na858cbd9w84e65b1dc2ed29f6@mail.gmail.com"
type="cite">
<div>Hi David:</div>
<div> </div>
<div> The streamline integrator sometimes is sensitive to the
selection of the initial step size (which is currently kind of large to
incur some issues, given a complex dataset particularly containing
multiple blocks of irregular boundaries, with some extreme topological
structures). Whenever possible, please use RK-45 (which may not
necessarily be slower than RK-2, particularly when your dataset is not
large) and small values for the step sizes (initial, max) as well as
the error threshold.</div>
<div> </div>
<div> In addition, care needs to be taken when using 'Mask points'
to select the seed points. Sometimes many resulting seeds reside
exactly on the boundaries between different blocks. In some rare cases,
such seeds may cause problems when 'OUT-OF-DOMAIN' status is detected
by the integrator.</div>
<div> </div>
<div> -Zhanping</div>
<div><br>
</div>
<div class="gmail_quote">On Fri, May 7, 2010 at 12:39 PM, David
Borland <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:borland@renci.org">borland@renci.org</a>></span> wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">I
have some steady-state vector field data that I am visualizing using
streamlines and particles via the following pipeline:<br>
<br>
Mask Points on the input (~100 points) to generate seeds<br>
Stream Tracer with Custom Source to generate the streamlines<br>
Contour on Integration Time to generate particles, which can then be
animated by animating the Isosurface value.<br>
<br>
This was working fine in v3.6.2, but started crashing in v3.8.0.
*Note: The crashing only occurs when the streamline filter output is
attached to a contour filter.* After some investigating, I realized
that part of the problem is with different default values for the
Stream Tracer in 3.8.0 vs. 3.6.2. From what I have been able to figure
out so far, it looks like different values for the Integrator Type
(default of Runge-Kutta 2 in 3.6.2 and Runge-Kutta 4.5 in 3.8.0) and
Initial Step Length (default of 0.5 in 3.6.2 and 0.2 in 3.8.0). After
experimenting with these values, I have found the following:<br>
<br>
<br>
Windows 3.6.2 64-bit binaries: Crashes for any Runge-Kutta with
Initial Step Size 0.5<br>
Works for any
Runge-Kutta with Initial Step Size 0.2<br>
<br>
Windows 3.8.0 64-bit binaries: Crashes for any Runge-Kutta with
Initial Step Size 0.5,<br>
Hangs for Runge-Kutta 4
and 4.5 with Initial Step Size 0.2<br>
<br>
Ubuntu Linux 3.6.2 64-bit build: Crashes for any Runge-Kutta with
Initial Step Size 0.5,<br>
Crashes for
Runge-Kutta 4.5 with Initial Step Size 0.2<br>
<br>
Ubuntu Linux 3.8.0 64-bit build: Crashes for any Runge-Kutta with
Initial Step Size 0.5,<br>
Crashes for
Runge-Kutta 4.5 with Initial Step Size 0.2<br>
<br>
<br>
The results on Linux seem to be more consistent than on Windows (go
figure...), and different data sets on Windows seem to have slightly
differnt behavior, but there certainly seems to be some interaction
between the initial step size and the integrator type. I'd be happy to
log a bug if that is more appropriate than posting to the mailing list.<br>
<br>
David<br>
<br>
<br>
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</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Zhanping Liu, PhD<br>
Kitware, Inc.<br>
28 Corporate Drive<br>
Clifton Park, NY 12065-8662<br>
Phone: 518-371-3971 x 138<br>
<a moz-do-not-send="true" href="http://www.zhanpingliu.org">http://www.zhanpingliu.org</a><br>
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