[Paraview] vtkDoubleArray with >3 components

[Shawn Waldon]

Hi Bruce,

SetNumberOfTuples reallocates the internal datastructure of the data array
to be the new required size based on the new number of components and
number of tuples.  This (combined with trying to clean up the old data from
SetArray) may be causing the heap corruption you are seeing.  Try setting
the number of components and number of tuples before adding the data to the
array.

HTH,
Shawn

On Tue, Jul 21, 2015 at 1:37 PM, Bruce Jones <bruce.david.jones at gmail.com>
wrote:

> Hi Cory,
>
> Sorry for the delayed response, I've hit another more serious bug which
> has been diverting my attention from this.
>
> Thanks for the state file, I haven't got it to work as I don't have numpy
> set up, but I have also got this working with 9 component arrays in
> paraview using a python script. However, I am now trying to port my python
> plugin to c++ which is where I am seeing the error.
>
> In my plugin I want to output a vtkarray for each vtkarray in the input
> dataset. The values in the output vtkarrays are interpolated from those in
> the input vtkarrays. Rather than working directly on vtkarray objects, I am
> allocating c++ arrays for each vtkarray, performing the interpolation, then
> creating vtkDoubleArrays and using SetArray to pass a pointer to my
> allocated c++ arrays to the output vtkarrays. The code for setting up the
> output vtkarrays is roughly as follows
>
>                 vtkPointData *pointData = input->GetPointData();
>                 vtkDataArray *dArray = pointData->GetArray(i);
> vtkDoubleArray *vtkDArrayAve = vtkDoubleArray::New();
> vtkDArrayAve->SetName(dArray->GetName());
> vtkDArrayAve->SetArray(dArraysAve[i],hgrid->GetTotalCells(),0);
> vtkDArrayAve->SetNumberOfComponents(numComponents[i]);
> vtkDArrayAve->SetNumberOfTuples(hgrid->GetTotalCells());
> output->GetPointData()->AddArray(vtkDArrayAve);
>
> dArraysAve is an array of pointers pointing to my c++ arrays
> hgrid->GetTotalCells() returns the number of data points for my output
>
> I also have another mode of operation for this plugin, where I perform the
> interpolation differently, in that function, if I make the call to
> SetNumberOfComponents() some heap corruption occurs and I get a segfault
> when I try to subsequently free my c++ arrays. Commenting out the call to
> SetNumberOfComponents avoids the segfault, but then I am limited to single
> component arrays. This is the more serious bug I mentioned, initially I
> figured they were unrelated, but I can't deny the number of components
> coincidence.
>
> Cheers,
> Bruce
>
> On Thu, 16 Jul 2015 at 14:41 Cory Quammen <cory.quammen at kitware.com>
> wrote:
>
>> Hi Bruce,
>>
>> I have attached a ParaView state file with a Programmable Source that
>> produces a vtkPolyData with 100 random points and a point data array with 9
>> components. It seems to display the various component ranges just fine.
>>
>> Best,
>> Cory
>>
>> On Thu, Jul 16, 2015 at 11:14 AM, Cory Quammen <cory.quammen at kitware.com>
>> wrote:
>>
>>> Hi Bruce,
>>>
>>> I haven't seen this, but ParaView may be interpreting this array as a
>>> tensor field. Do you have a smallish test data file that you can share that
>>> shows the problem?
>>>
>>> Thanks,
>>> Cory
>>>
>>> On Sat, Jul 11, 2015 at 11:14 AM, Bruce Jones <
>>> bruce.david.jones at gmail.com> wrote:
>>>
>>>> I am creating vtkDoubleArrays based on averaging some input data to a
>>>> reduced set of points. The input data includes various vtk arrays which
>>>> have 1, 3 and 9 components.
>>>>
>>>> After averaging, I am writing the data to c++ arrays, and creating a
>>>> new vtkDoubleArray using the SetArray() function to pass the c++ arrays.
>>>> This works fine for 1 and 3 component arrays, however for the 9 component
>>>> arrays paraview shows that every element is set to 0.
>>>>
>>>> If I hardcode it so that 9 component arrays become 3 component arrays
>>>> (reading only the first 3 components from the input array), then I get the
>>>> correct data for the first 3 components, though I obviously need the other
>>>> 6 components in the end.
>>>>
>>>> Has anyone encountered this before?
>>>>
>>>> Cheers,
>>>> Bruce
>>>>
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>>>>
>>>
>>>
>>> --
>>> Cory Quammen
>>> R&D Engineer
>>> Kitware, Inc.
>>>
>>
>>
>>
>> --
>> Cory Quammen
>> R&D Engineer
>> Kitware, Inc.
>>
>
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> Visit other Kitware open-source projects at
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>
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