[vtk-developers] Re: [ParaView3-Developer] Setting Update Extent

[John Biddiscombe]

[snip intro]

I found two things, which I believe are to blame for incorrect 
pieces/extents after temporal loop. Please anyone feel free to comment 
on this. cc'd to vtk-dev ...

In TemproralDataSetCache, I put an extent check in and overwrote the 
update extent. I remember doing this because pieces were not being 
transmitted, but now they are (or should be), so I've removed it.

The second is much nastier...
in

vtkCompositeDataPipeline::ExecuteSimpleAlgorithmForBlock(

there is a piece of code here...

      if (info->Has(
                    vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT()))
        {
        int extent[6] = {0,-1,0,-1,0,-1};
        info->Get(
          vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(),
          extent);
        info->Set(
          vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(),
          extent,
          6);
        info->Set(
          vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT_INITIALIZED(),
          1);
        storedPiece =
          
info->Get(vtkStreamingDemandDrivenPipeline::UPDATE_PIECE_NUMBER());
        storedNumPieces=
          
info->Get(vtkStreamingDemandDrivenPipeline::UPDATE_NUMBER_OF_PIECES());
        info->Set(
          vtkStreamingDemandDrivenPipeline::UPDATE_NUMBER_OF_PIECES(),
          1);
        vtkDebugMacro(<< "UPDATE_PIECE_NUMBER() (a) 0"  << " " << info);
        info->Set(
          vtkStreamingDemandDrivenPipeline::UPDATE_PIECE_NUMBER(), 0);
        }

which basically says if the whole extent exists, overwrite the update 
extent (of the input information).
Now looking at the key/values as it comes in, the UPDATE_EXTENT is 
actually correct - it was set earlier to the correct values - (question 
is, was is set before the cache was instantiated, in which case it's 
probably just luck that it's correct now), or was it set during the 
earlier request information. Either way, the check I show above looks 
like pants to me. It should at least be something like

if update extent not set .....

Imagine my surprise when the I changed it to that and it started 
behaving correctly.

Can anyone tell me why the original check was as it was. In the 
meantime, Berk is away it seems, so I'll sit on my fixes and run some 
tests until stuff breaks....

JB