[Paraview] SafeDownCast to vtkDoubleArray fails

[Geoff Draper]

I've never succeeded at getting ParaView to output to the console.  I 
usually just direct my debugging output to a log file.  If anyone has any 
tips for printing to stdout or stderr from within ParaView, I'd be 
interested to learn them.

On Tue, 23 Sep 2008, Natalie Happenhofer wrote:

>
> I tried that Print(cerr), but I didn´t see anything printed on my console.. I hoped that would give me information to which class my getArr belongs.
> thats the line where I used it:
>
> input -> GetPointData() -> GetArray(0) ->Print(cerr);
>
> I do not know what I should try next..
> NH
>
>> Date: Mon, 22 Sep 2008 09:18:00 -0400
>> From: burlen.loring at kitware.com
>> To: nataliehapp at hotmail.com
>> CC: paraview at paraview.org
>> Subject: Re: [Paraview] SafeDownCast to vtkDoubleArray fails
>>
>> Natalie Happenhofer wrote:
>>> Hi!
>>> Thx a lot, I get now a DataArray using
>>> getArr = scaldat ->GetArray(0); //I just have one array in my point data
>>>
>>> But still the downcast to vtkDoubleArray fails, here is the code I used:
>>>
>>> scaldat = input -> GetPointData();
>>> vtkDataArray *getArr = vtkDataArray::CreateDataArray(VTK_DOUBLE);
>>> getArr = scaldat -> GetArray(0);
>> This is going to create a leak, because you ask for a New() an array
>> then reassign your pointer to it before you call Delete().
>>
>>>
>>>  vtkDoubleArray *scalars = vtkDoubleArray::New();
>>> scalars = vtkDoubleArray::SafeDownCast(getArr); //this downcast fails,
>>> i.e at runtime I get that warning below
>> Again this results in a leak for same reason.
>>>  if(!scalars) vtkErrorMacro("SafeDownCast to vtkDoubleArray failed");
>>>
>>>
>>> With the member function "IsTypeOf(char *classname)" I tried to find
>>> out if getArr is an array of a subclass of vtkDataArray, but this does
>>> not seem to be the case. getArr is just a vtkDataArray. But I need to
>>> access the values in it!!!
>> There are a few reasons why the cast could fail. Do you know for sure
>> that getArr is not null? Could you check to be sure the array in
>> question is actually a double array? Try getArr->Print(cerr); That
>> should give more info. If this happened to me I would open the code in a
>> debugger and single step through this portion of the code examining
>> variables to see they have the expected values.
>>
>>
>>>
>>> thx,
>>> NH
>>>
>>>
>>>
>>>> Date: Sun, 21 Sep 2008 11:49:00 -0400
>>>> From: burlen.loring at kitware.com
>>>> To: nataliehapp at hotmail.com
>>>> CC: paraview at paraview.org
>>>> Subject: Re: [Paraview] SafeDownCast to vtkDoubleArray fails
>>>>>>> Natalie Happenhofer wrote:
>>>>> Hi!
>>>>> I need to cast my Point Data to a vtkDoubleArray, but it fails:
>>>>>
>>>>> vtkPointData *scaldat = input -> GetPointData();
>>>>> vtkDoubleArray *scalars = vtkDoubleArray::New();
>>>>> scalars = vtkDoubleArray::SafeDownCast(scaldat);
>>>>> if(!scalars) vtkErrorMacro("SafeDownCast to vtkDoubleArray failed");
>>>> PointData is not an array, it's a container of arrays. To get one of
>>> its
>>>> arrays see the GetArray methods.
>>>>
>>> http://www.vtk.org/doc/nightly/html/classvtkFieldData.html#888a6492210426d4ba4d358b87ab198f
>>>>
>>>> To find this in the documentation you would have to use the inheritance
>>>> diagrams. PointData "is a" DataSetAttibutes "is a" FieldData and so on.
>>>>
>>>>>
>>>>> and everytime I run the program I get that vtkErrorMacro.
>>>>> as far as I know from the input files, the PointData should be float,
>>>>> but casting to vtkFloatArray fails as well. Why? and what can I do
>>>>> about it?
>>>>>
>>>>> thx a lot,
>>>>> NH
>>>>>
>>>>>
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>>>>>
>>>>
>>>>
>>>> --
>>>> Burlen Loring
>>>> Kitware, Inc.
>>>> R&D Engineer
>>>> 28 Corporate Drive
>>>> Clifton Park, NY 12065-8662
>>>> Phone: 518-371-3971 x137
>>>>
>>>
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>>
>>
>> --
>> Burlen Loring
>> Kitware, Inc.
>> R&D Engineer
>> 28 Corporate Drive
>> Clifton Park, NY 12065-8662
>> Phone: 518-371-3971 x137
>>
>
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