[Paraview] Contours of streamlines crashing

[Zhanping Liu]

Hi David:

    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.

    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.

    -Zhanping


On Fri, May 7, 2010 at 12:39 PM, David Borland <borland at renci.org> wrote:

> I have some steady-state vector field data that I am visualizing using
> streamlines and particles via the following pipeline:
>
> Mask Points on the input (~100 points) to generate seeds
> Stream Tracer with Custom Source to generate the streamlines
> Contour on Integration Time to generate particles, which can then be
> animated by animating the Isosurface value.
>
> 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:
>
>
> Windows 3.6.2 64-bit binaries:  Crashes for any Runge-Kutta with Initial
> Step Size 0.5
>                                                Works for any Runge-Kutta
> with Initial Step Size 0.2
>
> Windows 3.8.0 64-bit binaries:  Crashes for any Runge-Kutta with Initial
> Step Size 0.5,
>                                                 Hangs for Runge-Kutta 4 and
> 4.5 with Initial Step Size 0.2
>
> Ubuntu Linux 3.6.2 64-bit build:  Crashes for any Runge-Kutta with Initial
> Step Size 0.5,
>                                                   Crashes for Runge-Kutta
> 4.5 with Initial Step Size 0.2
>
> Ubuntu Linux 3.8.0 64-bit build:  Crashes for any Runge-Kutta with Initial
> Step Size 0.5,
>                                                   Crashes for Runge-Kutta
> 4.5 with Initial Step Size 0.2
>
>
> 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.
>
> David
>
>
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-- 
Zhanping Liu, PhD
Kitware, Inc.
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x 138
http://www.zhanpingliu.org
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