[Paraview-developers] suspicious behaviour with structured Grids (in partuicular)

[Biddiscombe, John A.]

I've had a lot of problems with a particular set of filters of mine which resample SPH data onto grids. 

I have a Grid Generator class which is used as the sample location. This class outputs a vtkStructuredGrid.
When running in Parallel, I see very odd behaviour - which appears similar to a post I saw some months ago but can't find now, where the data displayed appears to be incorrect. Almsot as though the data from process 0 is being drawn on all processes and something is just not right, but I can't quite pin it down.

Because I have custom extent translators, dodgy extent manipulations and all parallel features, I can never be quite sure that it's paraview that's fundamentally broken or my stuff. 

However, in the case where the resampling grid is regular and axis aligned, the output could be vtkImageData, which I believe does work quite well in parallel, so I made a new stripped down resampler which outputs only image data. This works fine. The extent translation/manipulation is the same, the resampling the same, everything the same, except it produces image data.

This one doesn't crash or misbehave when run in parallel, however the image looks wrong 'first time' it is done, if I delete the filter, recreate a second one and then reexecute using identical settings, I get a completely different image and it looks perfect.

I really don't understand what is going on, but my feeling now is that paraview is broken somewhere deep inside (and is essentially unfit for purpose)

The problem is slightly less bad on 3.11 than on 3.10, but I still don't know what is actually wrong. I still don't know if I've messed up, or if ParaView is messing me up. (I have a complicated scenario where a multi-input filter passes update extent information from the second input).

I'm only posting this because I have some vague memory that someone else reported duplicated colours from process 0 on some gridded data in parallel and it's just possible, I'm seeing aspects of the same bug. I can't file a proper bug report because I'm still not completely sure a bug really exists. I'm just hoping someone reading this might mention something which triggers other thoughts, comments etc.

yours

JB


-- 
John Biddiscombe,                            email:biddisco @ cscs.ch
http://www.cscs.ch/
CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
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