[Paraview] Algorithm causing reader RequestData when running

[Paul Edwards]

Ah! I didn't know that and it fixes my problem.  Now I need to check
all my other plugins.....

Thanks,
Paul


On 26 March 2010 15:46, Berk Geveci <berk.geveci at kitware.com> wrote:
> Burlen is correct.
>
> On Fri, Mar 26, 2010 at 11:30 AM, Burlen Loring <burlen.loring at gmail.com> wrote:
>> If I'm not mistaken, when creating a VTK pipeline inside of a PV filter, you
>> need to make a shallow copy of the input dataset in order to keep the PV
>> pipeline isolated as your VTK pipeline executes.
>>
>> Try making a shallow copy of "input" and passing that into
>> "extractBlockFilter", and see if it helps.
>>
>> Burlen
>>
>> Paul Edwards wrote:
>>>
>>> Hi,
>>>
>>> I am writing an algorithm to operate on a vtkMultiBlockDataSet where I
>>> would like to extract blocks depending on field data that is set.
>>> Internally in my algorithm I am using the vtkExtractBlock filter and
>>> when this is updated it causes the RequestData for my reader to be
>>> executed again.  This doesn't happen when applying ExtractBlock in
>>> ParaView.  Below I have included an example RequestData that causes
>>> the data to be reloaded (note: this only happens when running in
>>> parallel):
>>>
>>> 8<-----------------------------------------------------------------
>>> int vtkTestMulti::RequestData(
>>>        vtkInformation* vtkNotUsed(request),
>>>        vtkInformationVector** inputVector,
>>>        vtkInformationVector* outputVector)
>>> {
>>>
>>>    vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
>>>    vtkMultiBlockDataSet* input = vtkMultiBlockDataSet::SafeDownCast(
>>>            inInfo->Get(vtkDataObject::DATA_OBJECT()));
>>>
>>>    vtkInformation* outInfo = outputVector->GetInformationObject(0);
>>>    vtkMultiBlockDataSet* output = vtkMultiBlockDataSet::SafeDownCast(
>>>            outInfo->Get(vtkDataObject::DATA_OBJECT()));
>>>
>>>    VTK_CREATE(vtkExtractBlock, extractBlockFilter);
>>>    extractBlockFilter->SetInput(input);
>>>    extractBlockFilter->AddIndex(1);
>>>    extractBlockFilter->Update();
>>>    output->ShallowCopy(extractBlockFilter->GetOutput());
>>>
>>>    return 1;
>>> }
>>> ----------------------------------------------------------------->8
>>>
>>> Can anyone see what I am doing wrong or provide any pointers for where to
>>> look?
>>>
>>> Thanks in advance,
>>> Paul
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>>
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>