[Paraview] gradient filter dumps core

[Moreland, Kenneth]

> The Gradient and Gradient Magnitude filters on a 3D  point, scalar,
> image data crashes Paraview version 3.2.1 on Windows XP x86_32 and on
> Ubuntu FeistyFawn x86_64.

So far I have not been able to replicate this.  I have used both ParaView 3.2.1 and ParaView CVS with the Wavelet source.  Can you tell us more about your data?  Can you send an example?

> Also note that Unstructured Gradient filter (following a Clip filter
> on the image data) works just fine. It is also curious that this
> filter has the "Result Array Name" output, which then appears in
> "Color by" list. There is no such output option in Gradient Magnitude
> filter. Is this by design?

That's an artifact of the filters being written by different developers and different times.  When yours truly originally wrote the unstructured gradient filter (outside of the VTK/ParaView repository), I broke convention because I needed both the original scalars and the gradients in the output.  I suspect the structured gradient filters don't follow a similar convention simply because they were written back when filters usually worked on "active" scalars rather than named scalars.

Because I'm conceited, I submitted a feature request to have the naming convention of the image gradient filters to follow the convention of the unstructured gradient filter.

  http://www.paraview.org/Bug/view.php?id=6693

-Ken